I was driving today and drove through a puddle. I heard a buzzing noise - at first, I thought the road was rough, since there was construction in the area. However, the noise got worse when I revved the engine, and it sounded like one of those 'riceboy' mufflers that they put on Civics with big wings. Ok, I thought, my exhaust pipe is broken between the cat and muffler. As I was pulling over to stop, the noise disappeared. I pulled over and checked the system, and there was nothing wrong.


Start driving again, the noise recurs after 2 miles or so, and again disappears before I have a chance to stop and check it out. It definitely _sounded_ like an exhaust leak, since it was RPM-dependent and I could hear popping when I was slowing down.


I get home, stuff the exhaust pipe with rags, tape them in and start the car. Ok, I think, this should uncover the leak if there is one. I let the car idle and listened for leaks - the only one that I could find was a minor one at the joint between front muffler and cat pipe.


I then revved the engine, thinking that that'd blow out any weak spots in the system. Instead, the rags blew out of the pipe with a loud 'pfffft.' And the leak from the joint that I noticed doesn't leak when the pipe isn't stuffed full of rags.


What do you all think? Could my car just be jealous since I was looking at a Subaru WRX for sale 2 blocks from me (just looking, I swear, don't have the $$$ right now :) ? Maybe it's a crack in the exhaust that's only opening up when the hot pipe gets wet - but I don't think a simple crack could make that much noise. Bad engine mounts, maybe (engine mounts are 2 yrs old, tranny mount is OLD, though).


The cat-back exhaust is less than a year old, Starla brand. The cat itself is god-knows-how-old, but the pipe going to it is newish and doesn't seem to leak. The noise was more of a noise rather than a vibration...


-b.