Tuning Tech. Subaru GR/VA STI Stumble, what is it? How to fix it the right way!

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  • Опубликовано: 4 янв 2025

Комментарии • 131

  • @FilthyHeathenKustoms
    @FilthyHeathenKustoms Год назад +3

    By far one of the best Subi vids I have found about the stumble. I just got my 1st wrx it's an 08. These cars are foreign to me I'm use to building and tuning Hondas. Definitely know what to look for now. And the stock map looks horrible. Definitely gonna do what you did and clean up the fuel trim. Thanks for the awesome work and video 🤘

  • @loganthompson2906
    @loganthompson2906 2 года назад +4

    amazing video man, thank you for the tips on the dreaded stumble. I did what you recommended and the stumble is gone. unbelievable I never thought the day would come.

    • @WT4T
      @WT4T  2 года назад

      Glad to hear!

  • @MattTr0n
    @MattTr0n 2 года назад +4

    Oh man am I glad I found this video. Dealing with this exact problem and I never knew this but I had an idea that "squid" was part of the problem. Thank you for explaining the technical side of it as it was very helpful in fully understanding the problem. 👍👍

  • @TrillMurray
    @TrillMurray 4 месяца назад +1

    Very informative. Thank you for taking the time to share this

    • @WT4T
      @WT4T  4 месяца назад

      You're very welcome!

  • @ricky_876
    @ricky_876 3 года назад +3

    I will definitely be sharing this video! Great video.

  • @russellwoolford179
    @russellwoolford179 8 месяцев назад +1

    Thanks so much dude ! Was trying to nut this issue out for two weeks kept seeing my trims max out at +25 around that 2700-3500 area and was noticing some det that was audiable in that area as the car is stock and quiet i will do this mod this weekend im really hoping my det issue also fucks right off 😅

    • @WT4T
      @WT4T  8 месяцев назад

      Yeah when it's really bad they'll audibly detonate from being lean 🫣

    • @russellwoolford179
      @russellwoolford179 8 месяцев назад +1

      @@WT4T scary times in the ej world lol fingers crossed not hammered big ends and crushed ring lands or it will be fresh short motor time 😬...i got all the parts today just set up up the reg and put sealant on all the fittings ...once its cures tomorrow hopefully i can drive more than 20% throttle without being paranoid af

  • @derrickgarcia303
    @derrickgarcia303 4 года назад +4

    Do you need a protune when removing the damper? Thanks!

  • @xlkazzlx4232
    @xlkazzlx4232 Месяц назад

    Amazing and very informative video. I have a GR

  • @Tyler-ld7bi
    @Tyler-ld7bi 2 года назад +2

    Do you have a link to your store for the squid delete? Or details on the hose barb and plug?

    • @WT4T
      @WT4T  Год назад +1

      www.preracing.com/products/preracing-fuel-damper-delete-kit-subaru-08-14-sti

  • @melvin_broh
    @melvin_broh 4 месяца назад

    Thanks, man. I have this issue in my 2015 STI after upgrading to ID1050X. Can I just delete the damper to see if that fixes the issue without an FPR?
    Also, does deleting the dampers require zeroing out the tables you showed in the video?

  • @deekithgames9975
    @deekithgames9975 2 года назад +3

    Hey I believe I may have this issue. Does it feel like your hitting a gust of wind while accelerating? Like a gap in the power band? Really only happens in 3rd and 4th the worst

    • @WT4T
      @WT4T  2 года назад

      Yup, right around 3000 rpm

  • @DJ_Driven
    @DJ_Driven 3 года назад +3

    Enjoyed watching your video was explained in detail where it made sense. My 2013 STi SE (was originally a CA car) when purchased used already had the "squid" removed. Thinking of doing a full fuel system hose upgrade with possibly a radium or making my own to get rid of the remaining mess in the engine bay.
    Curious what are your thoughts on why the Subaru engineers designed the fuel system like this some type of band-aid for emissions at the sacrifice of drivability and reliability?

    • @WT4T
      @WT4T  3 года назад +1

      I couldn't tell you why they do some things. The even more interesting thing is the "stumble" exists to some extent on ALL EJ platforms. Fixing it forever and perfectly would require a FPR with an infinitely long diaphragm spring, but that doesn't exist so really any full body FPR helps a TON. Also, running a series fuel arrangement instead of parallel helps as well even though most want to run parallel.

  • @bromando44
    @bromando44 7 месяцев назад +1

    I have a big turbo 2019 sti with a stumble AND an oscillating wave that has got me and my tuner scratching our heads... he said going stand alone to further tune it out will help but idk. im still thinking its a mechanical issue.

    • @WT4T
      @WT4T  7 месяцев назад

      It's partially mechanical, stand alone has its uses but generally won't fix this issue. You can email your modification list to willtunefortacos@gmail.com and I'll let you know if I see any red flags.

    • @bromando44
      @bromando44 7 месяцев назад +1

      @@WT4T i figured as much.. I cant afford stand alone for a while anyways. Oh man thanks! I seriously appreciate that! I'll put together a list and shoot you an email sometime this week along with some photos of the bay as well.

  • @gengiz
    @gengiz Год назад

    I just did a stage 2 with pro tune on my 2019 sti and I noticed if i ease into the power all the way to wot it’s fine but if the car is at say 2-3k rpm and I stomp on acceleration hard sometimes I get the stutter for half a sec then it clears and runs perfect. I spoke to my tuner who in Sydney is well known as reputable and he said it’s a known fueling issue on all sti 2008 onwards. I never had this issue when stock but I was told by friends and tuner that turbo back and cold air intake with 3 port boost solenoid would be maxing out my fuel
    System. It seems to happen on stage 2 sti’s mostly

    • @WT4T
      @WT4T  Год назад

      Typically, the "stumble" isn't an issue on a fast throttle event but rather just a cruising thing. I would need more information about your setup and tune to make a determination.

    • @gengiz
      @gengiz Год назад

      @@WT4T yeh mine definitely is only stuttering if I go wot from low rpm anything over 3.5k no issue or progressively going from idle to wot is also no issue

    • @WT4T
      @WT4T  Год назад +1

      Feel free to send a data log to willtunefortacos@gmail.com and I'll give it a look see when I get a chance

    • @tranwrx
      @tranwrx 2 месяца назад +1

      ​@WT4T question do u e-tune?

    • @WT4T
      @WT4T  2 месяца назад +1

      @tranwrx contact me at willtunefortacos@gmail.com and we can discuss options

  • @brennanm5645
    @brennanm5645 6 месяцев назад

    Hey with an aftermarket FPR does the fuel line stay pressurized even with the engine off? I was always taught with static pressure should hold tor awhile but that’s in my work on stock cars I don’t know about aftermarket FPRs though. My gauge on my fuel labs regulator drops to zero within a few seconds after priming and putting ignition in on position. Otherwise the pressure is fine at idle and otherwise. Pulls hard to 22psi on 93 internal watergate. It’s also there for a stumble fix. It takes a few extra seconds to start the car vs when it was new stock. The car is heavily modified with vent to atmosphere and ID1050 injector, built block, AEM 340 pump, TGV deletes, FP red turbo etc etc. Is this normal or do I have a leak somewhere?

  • @tranwrx
    @tranwrx 2 месяца назад +1

    May ask where did route your vacuum line

    • @WT4T
      @WT4T  2 месяца назад

      Usually factory unless I'm still having stumble, then I'll do it to the BOV source

  • @josephlemay
    @josephlemay 7 месяцев назад +1

    i assume when you do this first, do it before you tune the vehicle? not turn off the compensation after it is tuned

    • @WT4T
      @WT4T  7 месяцев назад

      Yes, it's ideal before as it will cause an overall change in fueling.

  • @johnnada3377
    @johnnada3377 2 года назад +1

    All I did to fix mine was move the vacuum reference from the cylinder 4 one, and splicing into the one for the bpv.

    • @WT4T
      @WT4T  2 года назад

      That helps some. Each piece helps a little until it's totally fixed. some cars you can get away with doing just one thing, others need everything.

  • @Eegoor1976
    @Eegoor1976 Год назад

    I installed the Cobb stumble kit on my 08 STI. Now I’m not reading any AF learning 1 on my Access-Port and I can’t build boost.

    • @WT4T
      @WT4T  Год назад

      Sounds like something was installed incorrectly or left unhooked. Where are you located?

  • @9THR33
    @9THR33 Год назад +1

    ok, so im chasing a fuel rich issue in my 2012 WRX (non-sti) and i found you and this stumble video. the 255 motor fuel system is different and does not have the 3 leg damper, it has 2 dampers but it does have a 3rd line, at this point in my research, im not sure what this line is, im still trying to understand my fuel system... can you tell me how this relates to my fuel system ? thanks tho, awesome video and explanation of this stumble.... that i think exists as well in my 255..... halpppp

    • @WT4T
      @WT4T  Год назад +1

      That 3rd line is evap vent line.

    • @9THR33
      @9THR33 Год назад +1

      @@WT4T hey. thanks. lol. forgot i had posted this. so yep, that same evening i commented i was able to figure out the 3 lines, feed, return and evap. still havent been able to deduce my rich at idle "problem". accessport showing -19 to sometimes maxed at -25. friend says possible bad injector(s) . other friends say oem injectors dont fail.... idk... I bought a fuel pressure guage to put on the feed, and an injector tester and pigtail to measure pressure drop after cueing the injector tester...

    • @9THR33
      @9THR33 Год назад

      @@WT4T how many tacos you need for some help on this fam?

    • @WT4T
      @WT4T  Год назад +1

      Eleven 😅 you can send your mod list and a log of the behavior to willtunefortacos@gmail.com

  • @Altprophet
    @Altprophet 5 месяцев назад +1

    Is this also a problem in the 2011 xlt 2.5t forester?

    • @WT4T
      @WT4T  5 месяцев назад

      Oddly enough, it's a problem in all subaru EJ turbos to some degree. Certain things and setups from the factory made it worse than others. Assuming that forester is a plastic manifold, it's probably not gonna be terrible, but there definitely could be some calibration things and mechanical setups that would cause it

  • @rc_p5192
    @rc_p5192 11 месяцев назад +1

    Ive done this to the comp table but still have the stumble... any ideas

    • @WT4T
      @WT4T  11 месяцев назад

      I would need more information on your setup

    • @rc_p5192
      @rc_p5192 11 месяцев назад +1

      2010 GR sti, rebuilt forged internals and pro tuned. Just upgraded to ID 1050 injectors and the stumble is worse. Have adjustable FPR teed into the BOV vacuum and stumble still remains. Trying to currently going through MAF scaling and zeroed out the comp tables.. no luck yet

    • @rc_p5192
      @rc_p5192 11 месяцев назад +1

      In fact the same FPR in the vid

    • @WT4T
      @WT4T  11 месяцев назад

      You can send calibraion to willtunefortacos@gmail.com and I'll take a look

    • @rc_p5192
      @rc_p5192 11 месяцев назад +1

      I watched your video over and over and over. You mentioned setting the FPR within 30sec when the fuel pump duty is at 100%. Ive never known this.. I did it and went for a quick spin.. the stumble has almost gone! Please let this be the problem solved. I will log more tomorrow to confirm and send you and my tuner to have a look. would appreciate any feedback you have then@@WT4T

  • @ravinglamb5917
    @ravinglamb5917 11 месяцев назад +1

    Is there a cheap fix like this delete kit for the GR wrx? Since it doesn't have the 3 leg damper?

    • @WT4T
      @WT4T  11 месяцев назад

      You can run this same regulator with a fuel rail adapter available here:
      www.preracing.com/products/turbosmart-fuel-rail-adapter

    • @ravinglamb5917
      @ravinglamb5917 11 месяцев назад +1

      @@WT4T Theres no cheaper option like the damper delete kit for the wrx correct?

    • @WT4T
      @WT4T  11 месяцев назад

      @ravinglamb5917 it's not needed for that year. If you need an adjustable regulator for additional fuel delivery then that link will get you the adapter you need. If you're getting stumble on a GR WRX there's something else going on.

    • @ravinglamb5917
      @ravinglamb5917 11 месяцев назад +1

      @@WT4T Oh is the stumble different from the constant bucking or hesitation I get at the 2500-3000rpm range if cruising at a set partial throttle?

    • @WT4T
      @WT4T  11 месяцев назад

      @ravinglamb5917 well, it might be similar feeling but on the WRX it's going to be a completely different cause.

  • @changyoua
    @changyoua 5 месяцев назад

    Do you set the fpr on cold start or warm start?

  • @AmirPomen
    @AmirPomen 2 года назад

    Does the load compensation map exist in GD chassis well?
    My hD swap forester still have abit of those stumble even after removing fuel damper, aftermarket bigger diapham regulator, direct fuel pump harness (constant 100% fuelpump duty) an an6 parallel equal length fuel line and rail...
    The most often the stumble happens when at partial load around 2.k~3k rpm loaded with 6psi boost...

    • @WT4T
      @WT4T  2 года назад

      Side feed car? There's a whole assortment of issues related to pulsation on side feed cars, there's a variety of fixes but the best one is top feed conversion.
      The tables are there in all the 32 but cars but they aren't used heavily. Most are zero everyehere but idle.

  • @FromPlsNerf
    @FromPlsNerf 3 года назад +1

    I may have missed it but does this car have stock injectors? My 2017 STI is Stage 2...accessport, ebcs, sf intake, aem fuel pump, invidia catless downpipe and r400, iag aos, exedy stage 1 hd clutch. With the colder winter temps, at WOT my IDC is getting pegged at 90-97%. I have been considering upgrading to ID 1050x injectors because I want to go flex fuel in the future anyway. Will upgrading the injectors exacerbate this stumble issue? Is it worth upgrading the regulator and stuff with the injectors or can that wait until I move to flex in the future?

    • @WT4T
      @WT4T  Год назад

      I can't recall if it had injectors but yes upgrading injectors tends to make this issue worse. Adding the regulator will actually allow you to turn up base pressure slightly to get more headroom out of your factory injectors too (you'd need to tune for this however)

  • @MrOhKali
    @MrOhKali 2 года назад +1

    Great video man! Great explanation and great work, one question. If I go with your stumble delete kit, do I need to tune it? Or can I just use your kit and drive it afterwards? If you can get back soon that’d be great! Thanks man

    • @WT4T
      @WT4T  2 года назад +1

      No requirement for tunning. You should notice some reduction in stumble right away and with additional calibration you'll notice even more.

    • @MrOhKali
      @MrOhKali 2 года назад

      @@WT4T sounds good! Thanks for the quick response man! 👍🏼 definitely gained yourself another sub 🙌🏼

    • @MrOhKali
      @MrOhKali 2 года назад +1

      @@WT4T also, where can I buy your kit from?

  • @RevKali
    @RevKali 2 года назад +1

    Just bought my 2017 STI about a month ago and it started doing this in 3rd and 4th gear around 5k-6k rpm. They sell a regulator kit but I would like to avoid that and do what you did, would you recommend me to do it as it is my daily car?

    • @wolfeSti
      @wolfeSti 2 года назад

      Sust did this to my car. Installed id1050s and it started to stumble BAD. This completely fixxed the problem. No knock, its dosnt run lean, just plain works

    • @WT4T
      @WT4T  Год назад

      I recommend it on ALL gr/va sti's!

  • @christianaraujo9956
    @christianaraujo9956 Год назад

    Where can I purchase this kit??? Does anyone know, I do not see a link anywhere.

    • @WT4T
      @WT4T  Год назад

      Here is the PREracing kit. The turbosmart one is pieced together from components but we can get you all the parts if you need.
      www.preracing.com/products/preracing-fuel-damper-delete-kit-subaru-08-14-sti

  • @JabyDragon
    @JabyDragon Год назад

    What software are you using to work on your Subaru's? I noticed you have a toughbook cf-52 maybe 53 I have 52 I am trying to use to tune my Subie.

    • @WT4T
      @WT4T  Год назад

      I think I'll do a video on this, stay tuned!

  • @cossavard
    @cossavard Год назад

    Is this still an issue on the VA20dit? I am pretty sure I'm having this issue right now on my 2020 WRX. Also, I know mine is high pressure direct injection, is that 43.5 psi still apply for the fpr, or will I be in the 60's

    • @WT4T
      @WT4T  Год назад +1

      On your car everything is quite a bit different. The low side fuel pressure will run a static 58psi And the high side pressure can be anywhere from 500-2000+ psi. Typically I'm an FA20 if you have a stumble or hesitation it's because of carbon build up or a bad connector for your mass airflow meter.

  • @zackrides265
    @zackrides265 2 года назад

    I have a JDM GR STI and it has the stumble once it gets up to temp. This should work on the JDM 2 liter as well right??
    My car is stock except for an exhaust, this should require me to get it tuned right?

    • @WT4T
      @WT4T  2 года назад

      I don't know the orientation of the fuel lines on the JDM cars but if they're the same as the usdm ones then it should help for sure!

  • @paulkorobkov3658
    @paulkorobkov3658 2 года назад

    Question: would ots tunes have this map zeroed out ahead of time or will one have to reach out and get a custom map made

    • @WT4T
      @WT4T  2 года назад

      No, ots maps rarely touch these values. Some might modify them slightly but I've never seen them zeroed

  • @justintracy1374
    @justintracy1374 2 года назад

    my 08 legacy spec b iag block upgraded injectors and pump has this issue ... can i do this to my car??

    • @WT4T
      @WT4T  Год назад

      Yes you can and I whould recommend it

  • @jimbrown9967
    @jimbrown9967 2 года назад

    Do you need to tune this fuel damper delete or can you just take it out and that’s it ready to drive

    • @WT4T
      @WT4T  2 года назад +1

      As stated in the video, you can just run it and it'll help some but tuning will allow it to help more.

    • @jimbrown9967
      @jimbrown9967 2 года назад

      @@WT4T thanks I’m gona give it a try

  • @ethanhenegar4611
    @ethanhenegar4611 3 года назад

    Do you need to tune for the removal of the damper? I have accesstuner and would like to know what I need to change

    • @Hello_its_me_mario
      @Hello_its_me_mario 3 года назад

      How did u get the access tuner

    • @ethanhenegar4611
      @ethanhenegar4611 3 года назад

      @@Hello_its_me_mario you have to take cobbs bs class, it costs 150$ and they literally teach you jack shit. You can call and ask for help from multiple tuners and they blow you off. My advice if you don’t have anyone who can teach you, get an etune and don’t waste money like I did.

    • @WT4T
      @WT4T  Год назад

      Not required but it helps

  • @jimbrown9967
    @jimbrown9967 2 года назад

    My 2008 sti hatch seems to hold the revs in low gears before shift.I put my clutch in and takes while to drop revs also if I leave it in gear itl rev up to like 3k any advice

    • @WT4T
      @WT4T  2 года назад

      Has the car been tuned ever? Is it all stock?

    • @jimbrown9967
      @jimbrown9967 2 года назад

      @@WT4T
      Thanks for getting back.. it’s been tuned but the problem still there after tune.it’s got a built bottom end cobra exhaust standard turbo Perrin induction with Perrin filter.

    • @jimbrown9967
      @jimbrown9967 2 года назад

      @@WT4T
      RTS competition clutch, mishimoto intake, water pump, oil pump, RCM head gaskets, RCM timing kit, spark plugs, Perrin cold air induction kit, ARP head studs, cosworth bearing kit, Mahle forged pistons, full gasket kit, forge Bov

    • @WT4T
      @WT4T  2 года назад

      Have you had a smoke test done to find any possible leaks on the induction system?

  • @JC-zt1bq
    @JC-zt1bq 4 года назад

    Good vid! Knowledge is power...Curious... What did you make on the dyno after the fix and tuning

    • @WT4T
      @WT4T  4 года назад +1

      I think it did 304whp and 330tq. Pretty average s2 GR STI power

  • @omarvargas1525
    @omarvargas1525 3 года назад

    If i’m already tuned and stumble persists, can I install this correction and not need another tune?

    • @WT4T
      @WT4T  Год назад

      You might, it won't hurt to install it and see though.

  • @ricky_876
    @ricky_876 3 года назад

    Can I get that piece of pipe to buy or you made it?

  • @nigeljoycey5644
    @nigeljoycey5644 3 года назад

    Just got a 2019 sti with only 18k kms on it. Completely stock. It is stumbling quite a bit in second gear, feels like its pulling timing and/or boost especially between 4k-5k rpm. Feels terrible to drive. I took it to the dealer and 3 different techs took it out for a drive and they all said they didn't feel what I was talking about. They plugged it in to read the ecu and said its all within spec. I told them its the fuel pump or some other fuel related issue and they just said its probably because of the hot weather and basically called me dumb. Really frustrating.

    • @WT4T
      @WT4T  3 года назад

      It's not any of the things they told you about. It's the GR stumble and it's 100% fixable! Just get the squid delete we sell and a custom map to fix the programming issues.

  • @brysonfitch5065
    @brysonfitch5065 3 года назад

    Please do a video on how bad the gfb bov is !!

    • @WT4T
      @WT4T  3 года назад

      I did, it's on my old channel @uhlmane I think.

  • @Knoss0s
    @Knoss0s 3 года назад

    Do you need to tune the car if you ONLY install that regulator?

    • @WT4T
      @WT4T  3 года назад

      Installing the regulator without programming will leave the fix the factory put in. Typically it's better than nothing but to fix it fully you need to program as well. I can write you a modified OTS calibration if your car is stock or lightly modified. DM me on instagram @willtunefortacos

  • @kzz8971
    @kzz8971 3 года назад

    Does this apply to the Sedan as well (GV)?

    • @WT4T
      @WT4T  3 года назад +1

      All 2008+ STI specifically.

  • @whocares5188
    @whocares5188 3 года назад

    My 2015 sti will randomly die while driving. It happens at any speed. It has a built short block basic bolt ons. Catless down pipe and up pipe. Tubo inlet. Short intake. And a pro tube. I have put 10k miles on that set up with no problem. For last 2 months car will randomly die it could happen twice in a day then not happen for 2 or 3 weeks. I replaced the fuel pump. Didn't fix it. What do yall think I should look it. I believe it's fuel bc sometimes before it dies it will stumble real bad but most the time it just dies with no warning. It will start right up like nothing happened.

    • @WT4T
      @WT4T  3 года назад

      Who built the motor? I ask because built motors are natoriously setup wrong and excessive "crank drag" can cause all the idle tables to be off. What weight oil? Did it just start once it got hot out. If you want i can review logs. Send a message to me on Instagram @willtunefortacos and we can exchange information.

  • @Altprophet
    @Altprophet 5 месяцев назад +1

    Take the gas cap off, pull the fuel pump relay and start the engine, this will eliminate fuel pressure in the rails.

    • @WT4T
      @WT4T  5 месяцев назад

      These cars don't have a fuel pump relay. There is a way to do this but it's easier just to spit a little gas

  • @dnukem1722
    @dnukem1722 2 года назад +1

    Good stuff 👍🏽

  • @chayannecastellano7221
    @chayannecastellano7221 3 года назад

    Any tunes after the damper being off

    • @WT4T
      @WT4T  Год назад

      Not required but it helps

    • @chayannecastellano7221
      @chayannecastellano7221 Год назад

      @@WT4Twhere can i buy your kit?

    • @WT4T
      @WT4T  Год назад

      @chayannecastellano7221 www.preracing.com has them

  • @Saiyan21
    @Saiyan21 7 месяцев назад +1

    Great video and after looking in the comment section looks like my question was answered lol

    • @WT4T
      @WT4T  7 месяцев назад

      What was your question?

    • @Saiyan21
      @Saiyan21 7 месяцев назад +1

      If i had to flash my car with that table being zero after doing the fuel pressure regulator.

    • @WT4T
      @WT4T  7 месяцев назад

      How'd it work out for you?

  • @marcushunt2570
    @marcushunt2570 3 года назад

    You selling the billet kit yet?

    • @WT4T
      @WT4T  3 года назад

      I believe we're awaiting carb approval for online sales but we have them in stock and have been selling them im store

  • @daubinks
    @daubinks 3 года назад +1

    I appreciate you

  • @franny1179
    @franny1179 Год назад

    Car need to be tune after install a fuel pressure regulator

    • @WT4T
      @WT4T  Год назад

      Ideally yes, not required though as long as pressure is set correctly

  • @knurri
    @knurri 7 месяцев назад

    To let the pressure out of the fuel system, remove the pump fuse and crank for 5 seconds and the system will be almost purged of fuel.
    Nice camera placement, where your arms cut off everything you are doing. This is clearly not a "how to" video based on that alone.

    • @WT4T
      @WT4T  7 месяцев назад

      Sorry, my video isn't up to your standards, but it has helped hundreds of others fix their stumble soooo... 🤷‍♂️

  • @SonikJesus
    @SonikJesus Год назад

    Does the Cobb FPR kit fix the issue as well?

    • @WT4T
      @WT4T  Год назад +1

      They claim it does, in testing it's a slight improvement but not much and it's way to expensive.

  • @toothpicdinosaur3777
    @toothpicdinosaur3777 2 года назад

    Does this cause idle stumble as well?

    • @WT4T
      @WT4T  2 года назад

      Not typically. Idle issues are usually related to air leaks or tuning issues