Hope the inspector doesn’t catch it if he sees it in it that’s an automatic bill but do it the right way, bro this way your fuel mixture perfect cheating the O2 sensor of oxygen and exhaust makes the computer give it more fuel so you’re wasting more fuel, just fix it the right way like the car was madegood luck good luck
No the first o2 sensors b4 the verter don't need the anti fouler that's what makes your fuel mixture the ones after just tell you if the cat is broke or not
You have to go to a Mexican place. Some will even do this for you and charge you 3 to 500 bucks, then after you drive around and clear the code and pass smog, they put the car back on the lift and take back their spacer lmao
As a mechanic of 30 yrs I'm going to let you know with some of the older vehicles it will stop the check engine light. The only problem is when your catalytic converter starts going out it will eventually plug completely up and the reason it's going out is because because your engine is not running up to par the way it should be. Meaning that your engine cannot get rid of the exhaust gases so they will start to backup. Your engine will eventually stall and not run, and it will more than likely try to blow out your head gaskets from the exhaust pressure looking for a way to escape the engine if you keep running it. There is another problem with your engine there is a problem with your engine whether it be a misfire etc. Fix that and then replace your catalytic converter and you will be fine
I just took the cat off and and soaked it in sea foam and dawn soap and washed it out with super hot water. It wasn’t that dirty honestly I think it was just clogged somewhere near the o2 sensor and that’s what was throwing the light so after I washed it out it’s fine I drove it like 50 miles still no cel.
Clearly just saying they make them for the intended purpose, so if you were to search for them your result will be specific, simply clarifying what would otherwise be confusing.
I just replaced my maf and map sensors on my 09 honda accord lx and the p0420 code popped up. I have a brand new cat that was replaced last summer so that is not the issue. Will the foulers work for my car to pass inspection so i can have more time to figure out whats going on? We do not have smog tests in my state
This modification doesn’t works anymore.If your state requiring smog check every two years.Because now the Smog Tech requiring visually checking for these also they have new software checking timely amounts of smog getting into your car computer.
Some cars will trip a 02 sensor inactivity code if you do this. This worked in my 02 Hyundai Accent . My past 03 crv would trip the inactivity code every 6 months. My past 01 Jetta threw the inactivity code right away.
There is a small hole in the end. What ever size drill bit fits in snuggly, go the next size up and make the whole a hair bigger. Repeat until it likes it.
This only works with post cat sensors (bank1 sensor 2 bank 2 sensor 2), if you do this with a pre cat sensor (bank 1 sensor 1) ( bank 2 sensor 1) the car won’t know how much fuell it’s burning anymore, HORABLE FOR THE ENGINE
Luckily sensor 2 is almost always the problem. Only when sensor 1 goes out it’s because something is legitimately wrong or the sensor crapped out. Sensor two is more like a suggestion that won’t let you get new tags
Meu cruze acendeu a luz de injeção e deu esse erro. Vou precisar fazer uma viagem de 600km com o carro no início de julho, é tranquilo andar com a luz acesa e arrumar após o trajeto?
My 07 Honda accord had aftermarket Cat installed and now the OBD II sensor says my sensor “Bank 1” air/fuel ratio is what’s causing check engine light and nothing else was detected what so ever. Is it possible that all I need is a new sensor for bank 1 ? And does is it need to be OEM sensor ? I believe the OEM for my Honda accord is “Denso” and also does the sensor for “Bank 2” also have to be OEM denso brand ? They replaced the “Bank 2” sensor since they stole my entire CAT and almost the entire exhaust system and I’m wondering if the bank 2 sensor is aftermarket and somehow confusing the car and causing the Bank 1 sensor to mess up. I really need help bad with this because I can’t find any used cars at all what so ever In the $8,000 price range that have less than 120,000 miles with good gas mileage and all I can find all over Northern California is the stupid ass “09’ Toyota Yaris” in my price range that’s decent on gas and I do not like anything about that car so I really need help whoever reads this message and what I should do ? Will the aftermarket CAT pass smog if I have OEM sensors in bank 1&2 ? Or is it possible the CAT itself even with brand new OEM sensors still fail smog if I replace the sensors with Denso brand OEM ? Please help haha 😂 I have 178K miles on my Honda and it runs amazing even with the issue I have rn… not a single issue besides this problem. What should I do y’all ? Thank you! I have the PO420 code and says Bank 1 sensor. When they put bank 2 sensor on the new aftermarket cat I wasn’t told if it is aftermarket sensor or OEM either. Do I need to replace both with brand new denso OEM ? And even if I do will it pass smog even with the aftermarket CAT ? I don’t wanna have to buy a new car or a new cat..
My 2014 Hyundai Sonata has had this code on and off I replaced my cat 3 times and got a whole new exhaust with a new aftermarket muffler and it smells like gas when it’s running really bad. Going to replace my O2 sensors soon hopefully it’s a bad sensor.
My Honda Accord 2009 Stalled After I Drove Through High Waters But After A Few Tries It Started Again But With The Engine Light 4 Years Ago And Was Told The Catalytic Converter Is Bad, That’s The Code That Comes Up. As I’m Driving Sometimes Exhaust Smells Permeate The Interior Which Smell Like Rotten Eggs. Also Somehow I’ve Managed To Pass DMV Inspection 4 Years Straight With A Check Engine Light & Bad Catalytic Converter. Is That Bad Catalytic Converter Endangering My Life?
Dont put em on the pre-cat sensors (upstream) . This is only a hack for downstream sensors, and if'n you get caught, the state will give you the ol stinky pinky WITHOUT the common courtesy of a reacharound. But if your willing to risk it, F*c* em anyway. But dont put them on the upstream sensors. It'll play ALL HELL with your entire fuel delivery, mixture and anything else associated with the computer trying to compensate for the false reading of the lack of gases it believes its registering
I bought one, I have four 02 Sensors on my lincoln. Do I use 1 or 4? Going to replace all four this week when the weather breaks. The emissions techs plug into my car, no chance of them seeing them, or is it a good idea to use it?
Curious about the drill out as well because I’ve seen it for other videos and vehicles but they have it at your auto parts store for like five bucks apiece. I’m at an AutoZone about to pick them up now I just wanted to see a few more videos before I did so, and saw your comment/question
@@brasha78 I already did all of this and passed my inspection. I used a spacer I bought from Walmart website. No drilling is required. Type in "o2 sensor car cel fix". I tried the ones from Autozone and they have to be drilled.
@@senderoverland , I just got my catalytic stolen during rainy day. After changing myself buying from the after market for cheaper price plus denso plugs still got 420 code now I am also looking for cat extension. They don't sell in e bay , just goggle from Wal-Mart part mail. Still waiting mine to solve the problem.
Actually yes and no. Some cars modules are more tedious and sensitive than others so it might not always work. I don’t suggest but that’s up to you. Signed: MASTER TECHNICIAN
Why not just use Cataclean, had a p0420 on my 01 integra and everyone said it was the Cat and the cataclean fixed it in 1 day. CEL went away on its ownand passed smog
Tried that code went away for a few days then came back took my cat off a yesterday and it was COMPLETELY clogged so if it comes back for you that's the next step
That's only in Democratic states. Republican states don't care about emissions. We don't even have inspections anymore here in Oklahoma and they are doing away with them in Texas as well
lol no. I mean this will work out 30% of time. Just replace the root cause of the problem. Which is not 02 sensor. Sometimes it just is gasket failure, sometimes bad substrate. But rarely o2 on a 0420 code. 😂
@@user-ui1lj8vi1y its illegal to trick ECU fake pass emmision it varies by state also its illegal in the hole country to on fed gov side do some research youll get you answer if you dont believe me
Isn’t a long term fix, usually caused by cats failing, will it work temporarily to buy you a little time, yes…….but your cat has/is failing, as it clogs it’ll heat up nuke itself into slag or clog completely causing the engine to have high back pressure and not go…….its quick and dirty cheap TEMPORARY “fix”
Cost lots of 💰 and headache after got mine stolen on rainy day. After buying Cat after market for cheaper price then code 420 to fix will cost more now.
This is dangerous advice, if the cat or cats are actually heavily restricted, the back pressure is going blow up the motor, eventually after some coil packs or distributor takes a poo
Guess I'll drive with bad tags like half of the people in this city do.
I haven’t seen a lazy tech check my 01 accord yet in Ca. Been 5 years still going strong
I just did this with only one spacer and it did work I just wanted to get it inspected I will fix the cats later
The check engine light came off?
Hope the inspector doesn’t catch it if he sees it in it that’s an automatic bill but do it the right way, bro this way your fuel mixture perfect cheating the O2 sensor of oxygen and exhaust makes the computer give it more fuel so you’re wasting more fuel, just fix it the right way like the car was madegood luck good luck
no you won’t bud
Is just a trick to get the inspection done but it does work because I did it myself I have an 08 TL Type s
No the first o2 sensors b4 the verter don't need the anti fouler that's what makes your fuel mixture the ones after just tell you if the cat is broke or not
I did that and got “FAILED TAMPERED” here in California yesterday :///
You went to the wrong station. Had mine on for over 5 years in Riverside. Nobody checks there
@@stevesmith756do you recommend those Mexican owned smog places?
@@elmerllamas3792 yes I do 👍
@@stevesmith756lmk where in riverside because I live around here to
You have to go to a Mexican place. Some will even do this for you and charge you 3 to 500 bucks, then after you drive around and clear the code and pass smog, they put the car back on the lift and take back their spacer lmao
Got a 06 crv and Same code just popped up. Gonna do this to save money. Thanks
Did this work? What does this really accomplish?
Did it work?
Does it work?
Did it even work?
As a mechanic of 30 yrs I'm going to let you know with some of the older vehicles it will stop the check engine light. The only problem is when your catalytic converter starts going out it will eventually plug completely up and the reason it's going out is because because your engine is not running up to par the way it should be. Meaning that your engine cannot get rid of the exhaust gases so they will start to backup. Your engine will eventually stall and not run, and it will more than likely try to blow out your head gaskets from the exhaust pressure looking for a way to escape the engine if you keep running it. There is another problem with your engine there is a problem with your engine whether it be a misfire etc. Fix that and then replace your catalytic converter and you will be fine
Lmao I got busted today with that on my car at the damn star station
You mean you did what he is doing and still failed emission test?
Same I did this a couple weeks ago and the guy looked under and saw them.
I just took the cat off and and soaked it in sea foam and dawn soap and washed it out with super hot water. It wasn’t that dirty honestly I think it was just clogged somewhere near the o2 sensor and that’s what was throwing the light so after I washed it out it’s fine I drove it like 50 miles still no cel.
@@cadenator-lt9kc 🤣🤣
@@cadenator-lt9kc When you stacked it, did you just pour them in together at the same time?
this is what i do after i knock out my cats. only use on down stream o2 sensors the top one is the the fuel injection dont fuck with that one
*EPA has entered the chat*
Hilarious 😂
I been lol for this guys comments😊😊😊😊
Screw epa fix it right the 1st time why let your car run like crap
Works with some, not all ! And if your state does an inspection with mirrors. It’s an automatic fail, depending on how knowledgeable the inspector is.
paint it brass color.
Didn't work on mine ford escape 2010 😢 I did 1 and 2 spacers and nothing
Won’t doing this run the risk of causing a fuel system open loop because the computer is sensing the o2 downstream isn’t getting hot enough?
Down stream has nothing to do with fuel mix. It just senses the cat con's effectiveness. Why can't they make things simple! : )
Do i need to do both sensors or just one ?
Its actually called a oxygen sensor adapter and they come with a screen at the end ....also have them elbowed
Actually the ones in the video are good old fashion spark plug anti foulers like it clearly says on the package
Clearly just saying they make them for the intended purpose, so if you were to search for them your result will be specific, simply clarifying what would otherwise be confusing.
I just replaced my maf and map sensors on my 09 honda accord lx and the p0420 code popped up. I have a brand new cat that was replaced last summer so that is not the issue. Will the foulers work for my car to pass inspection so i can have more time to figure out whats going on? We do not have smog tests in my state
This modification doesn’t works anymore.If your state requiring smog check every two years.Because now the Smog Tech requiring visually checking for these also they have new software checking timely amounts of smog getting into your car computer.
what is the size in MM for non fowler that you use?
If the smog test tech sees that with his under mirror you're fk.😎
Not if you’re like me and don’t check for cats 😎
Last couple years smog-ing my vehicles those dudes crawl up under my car and look down there
Bingo. People don't think good idea just the same.
Most of the country doesn't have to pass an emissions test or vehicle inspection
Not if they are your friends
My chevy captiva has this code the upper catalytic converter is bad . Starting to notice loss in performance and smell sulfur.
Some cars will trip a 02 sensor inactivity code if you do this. This worked in my 02 Hyundai Accent . My past 03 crv would trip the inactivity code every 6 months. My past 01 Jetta threw the inactivity code right away.
There is a small hole in the end. What ever size drill bit fits in snuggly, go the next size up and make the whole a hair bigger. Repeat until it likes it.
My Silverado kept tripping O2 inactive doing this too
This only works with post cat sensors (bank1 sensor 2 bank 2 sensor 2), if you do this with a pre cat sensor (bank 1 sensor 1) ( bank 2 sensor 1) the car won’t know how much fuell it’s burning anymore, HORABLE FOR THE ENGINE
Luckily sensor 2 is almost always the problem. Only when sensor 1 goes out it’s because something is legitimately wrong or the sensor crapped out. Sensor two is more like a suggestion that won’t let you get new tags
That’s a dumb comment. Sensor 1 has no business with cats
Your spelling is horable
Fuel treatment is the first resort
Explain please!
Amazon and Walmart have cat cleaners that you buy from the car fluid area in store. I use it for my Nissan Altima 05 and stops the sputtering
Wow that's good to know. So I will just ask for cat cleaner when I get to Walmart? So did that solved the problem and passed emission test??
i did use cataclean twice, but didn't help
Same, 2 bottles in 8 gallons of gas and I ran it hard at 75 mph for 45 minutes thinking that would do the trick. Nope. @@natenay5730
how long should I wait befor getting a smog check
Wow!!! This is definitely a 'how-not-to' video.
Meu cruze acendeu a luz de injeção e deu esse erro. Vou precisar fazer uma viagem de 600km com o carro no início de julho, é tranquilo andar com a luz acesa e arrumar após o trajeto?
My 07 Honda accord had aftermarket Cat installed and now the OBD II sensor says my sensor “Bank 1” air/fuel ratio is what’s causing check engine light and nothing else was detected what so ever. Is it possible that all I need is a new sensor for bank 1 ? And does is it need to be OEM sensor ? I believe the OEM for my Honda accord is “Denso” and also does the sensor for “Bank 2” also have to be OEM denso brand ? They replaced the “Bank 2” sensor since they stole my entire CAT and almost the entire exhaust system and I’m wondering if the bank 2 sensor is aftermarket and somehow confusing the car and causing the Bank 1 sensor to mess up. I really need help bad with this because I can’t find any used cars at all what so ever In the $8,000 price range that have less than 120,000 miles with good gas mileage and all I can find all over Northern California is the stupid ass “09’ Toyota Yaris” in my price range that’s decent on gas and I do not like anything about that car so I really need help whoever reads this message and what I should do ? Will the aftermarket CAT pass smog if I have OEM sensors in bank 1&2 ? Or is it possible the CAT itself even with brand new OEM sensors still fail smog if I replace the sensors with Denso brand OEM ? Please help haha 😂 I have 178K miles on my Honda and it runs amazing even with the issue I have rn… not a single issue besides this problem. What should I do y’all ? Thank you! I have the PO420 code and says Bank 1 sensor. When they put bank 2 sensor on the new aftermarket cat I wasn’t told if it is aftermarket sensor or OEM either. Do I need to replace both with brand new denso OEM ? And even if I do will it pass smog even with the aftermarket CAT ? I don’t wanna have to buy a new car or a new cat..
Is that the front or rear O2 sensor?
My 2014 Hyundai Sonata has had this code on and off I replaced my cat 3 times and got a whole new exhaust with a new aftermarket muffler and it smells like gas when it’s running really bad. Going to replace my O2 sensors soon hopefully it’s a bad sensor.
😂 keep throwing parts at it your down to 2 from 3 🤣
Sounds like dripping fuel injectors
Will this work on a CADILLAC STS??
My Honda Accord 2009 Stalled After I Drove Through High Waters But After A Few Tries It Started Again But With The Engine Light 4 Years Ago And Was Told The Catalytic Converter Is Bad, That’s The Code That Comes Up. As I’m Driving Sometimes Exhaust Smells Permeate The Interior Which Smell Like Rotten Eggs. Also Somehow I’ve Managed To Pass DMV Inspection 4 Years Straight With A Check Engine Light & Bad Catalytic Converter. Is That Bad Catalytic Converter Endangering My Life?
Wow you passed inspection with that check engine light on??
I have a 2005 Chevy Silverado has 2 upstream oxygen sensors and 2 downstream do I have to put 4 spark plugs non foulers??
Dont put em on the pre-cat sensors (upstream) . This is only a hack for downstream sensors, and if'n you get caught, the state will give you the ol stinky pinky WITHOUT the common courtesy of a reacharound. But if your willing to risk it, F*c* em anyway. But dont put them on the upstream sensors. It'll play ALL HELL with your entire fuel delivery, mixture and anything else associated with the computer trying to compensate for the false reading of the lack of gases it believes its registering
I bought one, I have four 02 Sensors on my lincoln. Do I use 1 or 4? Going to replace all four this week when the weather breaks. The emissions techs plug into my car, no chance of them seeing them, or is it a good idea to use it?
2 on the downstream sensors
Shmuks took my converters and now my 98 Silverado keeps running rich as hell on one side. I wonder if its the o2 sensors? Anybody have any advice? ✌
Spark plug non fouler is put on to the down stream 02?
On put on sensors after the cats. Not before cats.
Would this work on a 2012 Nissan Sentra with a bank 1 bad catalytic converter?
Did you figure it out? I have the same thing on my 2007 Sentra
If this after sensor by the engine by or near the exhaust ?up stream or downstream
There are a lot of opinions out there, but adding this only on lowest o2 sensor will work
Where did you get those whats the dimensions
Im using 18mm still dont sit flush even though i drilled a half inch hole yours look deeper
Walmart
Walmart
What size is this spark plug non fouler
Just did this on my ford escape 2010 v6 and it didn't work try 2 spacers 😢
Anyone have experience trying this with a dodge journey?
Will this fix PO137???
Works great
Thank you 😊
Did you have to make the hole bigger in the non-fouler? If not where did you get this piece?
Curious about the drill out as well because I’ve seen it for other videos and vehicles but they have it at your auto parts store for like five bucks apiece. I’m at an AutoZone about to pick them up now I just wanted to see a few more videos before I did so, and saw your comment/question
@@brasha78 I already did all of this and passed my inspection. I used a spacer I bought from Walmart website. No drilling is required. Type in "o2 sensor car cel fix".
I tried the ones from Autozone and they have to be drilled.
@@nicktt500 im having trouble finding it, sorry to ask but is there any way you could post a link? Id be extremely greatful!
@@senderoverland , I just got my catalytic stolen during rainy day. After changing myself buying from the after market for cheaper price plus denso plugs still got 420 code now I am also looking for cat extension. They don't sell in e bay , just goggle from Wal-Mart part mail. Still waiting mine to solve the problem.
@@ramosochoa418 Amazon has some great parts the autosaver 88 company is great for direct fit parts
Old skool trick
Try that on my Cadillac SRX doesn’t work 2007 4.6
Didn’t work for my ‘07 Cadillac CTS 3.6L…😢
Will this work on a 2004 Tahoe
Yes
I have seen these but with a small amount of catalyst material in them.
Steel wool packed in there works nicely too
That's not a fix 🤷 you can do that to trick the computer to pass inspection and doesn't fix the problem
Or delete cats and delete second o2 off pcm. That why she runs top notch.
I then the cats over time gets clogged and the back pressure blows your engine 🤦🏻♂️🤦🏻♂️🤦🏻♂️
Muy Bueno
You can get one of those with a little catalytic converter in it lol
I’m going to try it tomorrow stay tuned 😅
It's tomorrow. What's gone on!?!? Tell me!!!!
Been 2 weeks we’re is the update
@@Bryan_thegodhe is on jail😂. Iam joking, I will do this tomorrow, and I will give you my update, no fear 😎
@@ivanmiranda7what's the update do u need money on your books...lol jk
@@Bryan_thegod update: it worked great, but you must to clear the code using a car scanner.
Will I pass the emissions test with that piece connected? Thx
Actually yes and no. Some cars modules are more tedious and sensitive than others so it might not always work. I don’t suggest but that’s up to you.
Signed: MASTER TECHNICIAN
Did this and got p013e p0138 codes
bottle of rubbing alcohol used to work
How?
Why not just use Cataclean, had a p0420 on my 01 integra and everyone said it was the Cat and the cataclean fixed it in 1 day. CEL went away on its ownand passed smog
Tried that code went away for a few days then came back took my cat off a yesterday and it was COMPLETELY clogged so if it comes back for you that's the next step
It works better with a mesh screen on the tip of the extender
With a mesh?
@@eduardorojas2949 yeah it’s a metal mesh screen works great
Lol just clean the catalyst
Well, expect now to have a non-fuel efficiency.
Only works sometimes just had a customer come back yesterday cause his light came back on had to tune it and do catless for him now he’s happy
Are you adding this ones on the upper and lower o2 sensor ? Or just in the lowest sensor ?
Can i just unscrew the back o2 sensors and let them hang or will it still set it off
Shady. Doesn’t show the end of the adapter
Fix it the right way shortcuts lead to bullshit
You are not fixing anything, just bypassing the problem.....
Hospitals and pharmaceuticals
There is a reason why he doesn't do it on camera.
Just remember that if you get caught it is illegal, and if you get caught it's jail time.
That's only in Democratic states. Republican states don't care about emissions. We don't even have inspections anymore here in Oklahoma and they are doing away with them in Texas as well
Not here in California foo,
Didn’t work for me
Until it starts misfiring 😂
Until the cat clogs!
I wonder what a P0069 is!
What part # is the longer one
What is the part number for the long socket type you used? TIA
Spark plug anti fouler I would buy one of each thread and return the ones you don't need
@@robertg9334 perfect!! Thank you!!
You don’t wanna do something like that in a long one is Kakashi more money
It’s works but it’s not legal to do it
Don't have any cats 😂
Get a spark plug non-whatget a spark plug non what?
It doesn't work....
Doesn't work
Shhhhhhh 😏😉
throws off the fuel mixture
Not on a secondary post cat sensor code p0420
@@arnoldarnold1034 then why is it there?
@@gorporpio to measure the efficiency of the cat con. The one in front of the converter does the fuel mix 😁
@@arnoldarnold1034 thanks
So I have this code what do I do and what does it do
Facts lol
This doesn't work on modern cars
It's not a fix. It's a cheat. Does get rid of the code most times though
lol no. I mean this will work out 30% of time. Just replace the root cause of the problem. Which is not 02 sensor. Sometimes it just is gasket failure, sometimes bad substrate. But rarely o2 on a 0420 code. 😂
Ok then your car or truck will lock up and no longer be anygood wow
Just fix it
Stop showing people something that's illegal, and only works on some cars genius
That doesnt really fix anything.
how to fail emissions test in one easy step
if you want to go to jail or get a citation please proceed
Devo please explain why
@@user-ui1lj8vi1y its illegal to trick ECU fake pass emmision it varies by state also its illegal in the hole country to on fed gov side do some research youll get you answer if you dont believe me
You think anyone cares? If you fail emissions it's a 20$ fine till the next time. You ain't gonna go to jail lmaoooooooooooooo
The smog tech will noticed it during the inspection then what will happened?
@@blass5506 I just told ya. ^
This is just a bandaid for bigger problem you are not fixing. Do not do this.
There is a reason your CAT died on you.
yeah, it's called mileage. They wear out.
Well you do realize some cars don't react well to this hack & will make your Service Engine Soon light come on
😂
Isn’t a long term fix, usually caused by cats failing, will it work temporarily to buy you a little time, yes…….but your cat has/is failing, as it clogs it’ll heat up nuke itself into slag or clog completely causing the engine to have high back pressure and not go…….its quick and dirty cheap TEMPORARY “fix”
Indeed it is! People like cheap and dirty, this is America
Just fix the problem properly
Cost lots of 💰 and headache after got mine stolen on rainy day. After buying Cat after market for cheaper price then code 420 to fix will cost more now.
We only have inspections here in Memphis and Nashville all Republican areas don’t give a shit it’s a car
Except eventually the cat will harm performance and may clog or deteriorate. Just cut em off😎
If you're taking out the o2 sensor to put in a non fowler, you mine as well just change the o2 sensor you already have it out. Wow stupidity runs deep
"MIGHT as well" change parts that aren't bad? Yeah i guess you're last statement is right on the money
why change the sensor when it doesn't need changing?
Black tape is cheaper.
explain black tape plz
This is dangerous advice, if the cat or cats are actually heavily restricted, the back pressure is going blow up the motor, eventually after some coil packs or distributor takes a poo