Well i have an Exhaust leak on my 88 iroc 305. The whole system is stock. The pipes have mild to no weathering, mostly back by the rear wheel. It's really bad. The cat looks old and kinda deformed. Anyways, i had a leak, bad enough that i had a head ache for 2 days. I've noticecd that it really comes in when the heater is on. If i lay down by the cat and start the engine i can't smell anything. But it I lift the hood. It's really bad. Any ideas what it could be, where it's commin from, how to find it. Any help would be great. Oh and i heard if the cat stinks and it's old it's probably going out. So today i'm going to gut it and run in like that till I get the money for a new cat.

 

You've prolly already tried this but incase you havent...I've got an exhaust leak too, and it does the heater thing also so it could be the same spot. hold your hand about an inch or two above the exhaust manifold on each side and feel for some high velocity air. You'll know it if you feel it, and chances are your gaskets or manifolds are shot in that spot.

 

cool, i'll try it