IROCtheThird

iTrader: (15)

Alright, so about a month or two ago I bought a 89 IROC 305 TPI, it already had an aftermarket muffler, some knock off p.o.s., it started making these whistle that if you heard it makes you want to go crazy. So I found a bunch of holes and perferations in the muffler/intermediate pipe. The people at the inspection station said they couldnt get a reading which is crap cause I got plenty of a reading. So needless to say, time for a new catback. I already had a semi-new flowi i picked up for $40. I got the intermediate pipe, which was wrong so I had to have a shop customize for me, so I said just put the whole thing in. Get the car back, no exhaust leaks, but it whistles as if I never changed anything. There is nothing in my motor to cause it. I am thinking maybe in my cat/y pipe? Any info anybody? It drives me crazy, its super loud at low rpms and goes away after 2000. Any help is greatly appreciated.

Avernus

Maybe you have one of these. haha I joke. Well maybe there are holes in the top of your muffler. just keep building from the I pipe back. Maybe it's the headers or the Y pipe. You have to find it because we can't spend some quality time under there or just throw parts at it.

Fullsizewagon

I assume it's there at idle too? If so, how about trying to locate the sound? It might be a vacuum leak, maybe some gasket around the intake manifold has deteriorated?

IROCtheThird

iTrader: (15)

If I put my head underneath the car at the front, its not there, but as I start moving my head back I start hearing it, until I get to the back where its super loud. I have a brand new I pipe/muffler. Its only really there at idle, after 2000rpm it goes away. I have no vacuum leaks. I just replaced all the top end gaskets, there are no holes or leaks. My thought is that there is something in the cat or y-pipe. I guess I just have to check.