ok, i have a problem and i need advice.. I installed a custom true dual exhaust on my 03 coupe. A couple of hours after i was driving and the car started to miss fire, i turned the car of then back on again and it was fine again.. know it fine for a while then it starts to stumble(mis fire) again, i keep driving and it fixes its self then it starts again... The cycle keeps happening over and over again.. i still have the factory cats.. theres no cross over point on the exhaust system..spark plugs are new.. im thinking maybe not enough back pressure?
any help would be helpfull...

thanks..

 

that is wierd. Are u sure it is a misfire rather than raspy exhaust note? Does it happen all the time: for example hot/cold weather, WOT?

 

yes its happening all the time... no the car goes from a calm idle to a shake and a misfire. check engine light came on and know its blinking..

 

what size diameter tubing did you use? also did you do anything that may have damaged the O2 sensors?

 

i installed 2 resonators, one on each side and a x pipe. all the misfiring damaged the spark plug in cylinder number 1, i replaced it and the car runs perfect..

the car sounds sick now....

 

im glad it worked out. I wonder why this happened in the first place. How many miles did u have on the spark plugs?

 

plugs only had about 300 miles on them....

 

fawk having the same problem now....

car driving normal goes in and out of a misfire. I'll try changing plugs hopefully this cleans it up...

Interesting that the CEL blinks but it doesnt stay on so i can read the code with the scanner.

 

Could also be a fault coil pack