The engine isn't going to like not having a muffler. Air to fuel ratio is important for your engine to run properly. Without a muffler the air flowing out of your exhaust will likely run too rich with fuel and eventually the extra fuel will clog up the o2 censors, the cat, the MAP censor and the spark plugs. Once this happens the computer can get out of wack trying to correct the issue which will make the engine run real rough from time to time, could even cause you to have difficulty starting while hot or stalling out while idling after a hot start. Look up Jeep 4.0 heat soak or vapor lock. Besides being illegal and obnoxiously immature to intentionally drive without a muffler you could actually screw up your engine. No skin off my back though, the more people that destroy their XJ's out there the higher the value goes on my 100% stock low miles rust free XJ. I guess I should be thanking you. All kidding aside, if you throw a muffle back on there your 4.0 will thank you. Good luck.
Did some research…you have no idea what you are talking about. 3 cats won’t make the fuel run rich. Vapor lock happens when fuel atomizes in the fuel rail from high engine temperatures. None of that has anything to do with what comes out behind the 3rd cat. Plenty of people run muffler deletes and nobody has issues from them. You came off like a real dipshit too.
![Jeep Cherokee: Muffler & Tailpipe Replacement - Flowmaster Super 40 Delta Flow [‘84-‘01 XJ]](/img/1.gif)
The engine isn't going to like not having a muffler. Air to fuel ratio is important for your engine to run properly. Without a muffler the air flowing out of your exhaust will likely run too rich with fuel and eventually the extra fuel will clog up the o2 censors, the cat, the MAP censor and the spark plugs. Once this happens the computer can get out of wack trying to correct the issue which will make the engine run real rough from time to time, could even cause you to have difficulty starting while hot or stalling out while idling after a hot start. Look up Jeep 4.0 heat soak or vapor lock. Besides being illegal and obnoxiously immature to intentionally drive without a muffler you could actually screw up your engine. No skin off my back though, the more people that destroy their XJ's out there the higher the value goes on my 100% stock low miles rust free XJ. I guess I should be thanking you. All kidding aside, if you throw a muffle back on there your 4.0 will thank you. Good luck.
Did some research…you have no idea what you are talking about. 3 cats won’t make the fuel run rich. Vapor lock happens when fuel atomizes in the fuel rail from high engine temperatures. None of that has anything to do with what comes out behind the 3rd cat. Plenty of people run muffler deletes and nobody has issues from them. You came off like a real dipshit too.