Rep Power: 265

i just put on my cat back exhaust......and it sounds fine and all but after a while.......of driving......like if i went on the freeway or something, the middle pipping starts rumbleing as if......its backfiring.......it rumbles right under my passenger seat........what is it?.......what could it be?.........

 
Rep Power: 453

was it raining when you were driving? This usually happens in the rain with aftermarket exhaust. Also get under there and wiggle your exhaust around and see if it hits anything. It might be hitting the heatshield or the upper part of the car.

 
Rep Power: 265

thanx.........that makes sense....maybe cuz i washed my car......and probably got water in there......or something.....thanx.....

 
Rep Power: 0

No, iy has nothing to do with you washing your car. It is just a bad fitment exhaust or bad install and is hitting the underside. What brand did you go with?

 
Rep Power: 453

yea washing your car shouldnt have any effect on it. I was saying if you are driving in the rain, it happens, but like bobbyd said, it is probably hitting underneath the car somewhere, and it just need more support or moved around a bit.

 
Rep Power: 265

i got an espilar exhaust.......and u guys were right.....it is hittin the bottom of my car.........the heat shield......and stuff........it vibrates too much

 
Rep Power: 0

That sucks man. I just got rid of my cat back and got an axel back because of mine hitting too.