So, ever since I installed my header and catback my car has been acting weird. Now, I'm not sure what causes it but it only does it at idle... Today was the worst, stopped at a stop light and my car starts to idle and suddenly it sounds like a helicopter is going overhead, but it turns out there wasn't, it was my CAR. I mean, it was so loud, it sounded like an actual helicopter going over head. Then when I started to go it quit. Then I stopped at the next light and it didn't do it. Very random and odd, it did it when I got pulled over the other night, and at work one day. Now, it's done it when I was heavily on it and came to a stop and then today I was barely on it due to the icy roads and it still did it.......

Anyone have any idea what it could be? I read about the "knock" and I guess you can say it's a knocking noise...


ugh........... that and after I did my exhaust, something in my rear end is making all sorts of ******* racket, I hope I didn't jack it up on something wrong and **** up my suspension.

 

Sounds like you need to check the heat sheilds to make sure they are tight.

If rear noise started after the install, and you didn't do anything to the suspension, maybe you have clearence issues with your exhaust, or its not securly mounted.

 

It's probably your exhaust banging off the rear beam that you are hearing from the rear. From what I have heard the 3 in exhaust is a tight fit and does cause some noise.

 

Heat shield and hangers. Look for loose stuff and clearance issues. Something is banging against something else.

 

I'll just take it to the local shop and run it up on their lift and check it out. I'll beat up all the heat shields with a hammer - lol.