Exhaust noise.... help!!!

[yz250]

I just got a Mac o/r H pipe installed on my '01 Cobra. There is an annoying ticking/hissing/vibration deal coming from what seems to be under the drivers side dash when i accelrate (very noticible low rpms). Can't tell if it's inside the car or not. The more gas i give it, the faster and worse it gets. Is this normal vibration or could I possibly have a leak, although the guy who put it on said he checked for leaks and there weren't any. What is going on... Thanks.

 

[CottonBurnerz]

If it TICKS then it's a leak (ticking will get faster if you accelerate). If it hiss then it might be a leak but unlikely... hopes that helps

 

[mity2]

my old MR2(with cracked manihild) used to hiss during deccelation. turned out it was piston sucking air. Oh, and it ticked BAD.
Your H-pipe mostlikey has famous driver side ball&socket fitment issue