Either you messed up an O2 sensor or your tune is mega off from the new exhaust. Normally exhaust doesn't affect the driveability much, unless you have other problems to start with that just get compounded buy the better flow. i.e. Bad plugs, wires, loss in compression, stuff like that.


You should chill out! And, maybe type with some clarity and full words. I'm not a post natzi but your thread is less than standard.

 

Your O/R X pipe will trigger the check engine light because your rear O2 sensors are reading that your cats are not working properly. That will not cause driveablity problems the check engine light just means that you will not pass an emissions test. If you have a tuner then just turn the rear O2s off. Then clear the codes and drive it. Check for any other codes after you drive it.

Give us a better description of what the car is doing wrong so we can help you better.

 

sorry about that. but when i floor it it fells like it back fireing.

 

Could it be your ****ty bbk o/r x pipe? Ive heard many people complain about the sounds bbk o/r x pipes make. Couple that with flowmasters and you could have some weird noises. Especially loud popping on the decel. The hesitation could be from your CEL. I know when mine goes on from the o/r midpipe the car runs like crap. I don't care what anyone says. When the rear O2s trip the CEL on my car it runs like hell.

 

it may also help to bring this issue up with the 5.0 section, according to your sig. that's what you have, and they would obviously be more relative to the problem you're speaking of.

 

no i have two cars a fox body and a 98 4.6 the 4.6 is the one thats acting up thanks mark for the help.

 

ok i whent and plugd in my handheld tuner and ther was no code and CEL didnt come on any more i took it for a ride and it didnt hesitate like it was so i dont kow what was worng with it but it still hesitates a little

 

check ur spark plugs for the back firing