My 2000 Trans Am threw a code for the cat converters going out this summer so I took it into our local Pontiac dealership where both cats were replaced for free. I just bought the car in April of 2008 and this wasn't an issue when I bought it. Well, the second I picked it up it made a horrible exhaust leak noise and smell was unbearable. I took it back the next day and sure enough the pipes going in were busted. They replaced those pipes but I still hear the sound faintly to mid and the smell is still apparent when I have vent or non circulation A/C. I brought it back and was told I was an idiot (course I am a woman so that helps a lot!) and then I took it to Midas and they again thought I was an idiot. We have tightened bolts, tightened everything in the engine to no relief. I had read back as far as I could in forum archives but couldn't find anything on this exactly. I know my car and know this isn't normal! Any ideas?

Thanks!

 

How many days has it been since you got the new cats in. I hear new cats have an eggy smell when they're new and the smell goes away eventually.

Kinda difficult to understand what sound you hear though...anyway to describe where on the car it comes from..engine, under car, near the rear?

 

It's not the egg or burning paper smell (which was god awful!). It smells like exhaust in my vents and the sound a muffled ticking sound from the engine compartment when I accelerate.

 

The exhaust smell could be getting sucked into the heater box from the engine compartment. You could take it to an exhaust shop, they have a tool for sensing exhaust leaks.

 

If they were yanking on the exhaust could a leak have developed at the manifold? I know the B-Body LT1's have a nasty habit of snapping the rear bolts holding the manifolds to the head.

 

I would take it to a few other places to get their suggestions on what could be the problem and then take it back to the Pontiac dealership.

 

We were thinking it might be in the upper-engine area since we have tightened the bolts underneath the car a number of times. We will take a look at the manifold more closely (took a peek when we were on our way into the house) and see if there is any loose bolts/dust. If we can't see anything I will take it to our old friend who has a small shop when I get more cash flow. I had taken it back to Pontiac immediately and they told me I was crazy and then I took it to Midas which specializes in mufflers-exhausts and they were just as stupid. Then they broke my mirror bracket by leaning on it (looks like previous owner ran into a wall at one point) and that has been a nightmare to find. Really sucks cause the noise and smell weren't there before they touched it!

 

An exhaust leak will have a ticking sound. If you can pin down the area maybe you can find the leak if its there.

 

My assumption is that you have an LT1 engine F_body.

The left side gasket is very difficult to seal since the flange does not have a equal-distant bolt space pattern that will allow UN-equal clamp load. The typical gm "gasket" is not an easy thing to align, and, if the flange surfaces are not parallel, there will be an exhaust leak. The leak is usually near the head region when clamp load is low. This has happened to me many times in the past (I'm very modded now). I run a 0.005" feeler gage into the flange gap to test for closure of the gasket interface.

The left side header can run hot due to an air leak causing the PCM to adjust the AFR (and, the smell). The Left side pipe must be completely loose and torqued to the exhaust manifold. Then connect the outlet end of the cross over.

Usually when things are done for free, you get a POS job. Sorry for your problem, but, most people just do not care. As Rush said... you want something done right, do it yourself. I'm pushing 800hp @ the fly, and, I would never let one of those HACKS tough my machine.
B.

 

That would be in incorrect assumption.

 

You didn't get the memo that they put left over LT1s in 2000 Trans Ams?

 

LOL no, no LT1. We had an LT1 (my husband's '95 Z28) but I am 100% positive my T/A is a LS1. :P I have a definite ticking sound which is loud in the cabin. It doesn't seem to make much noise on the outside. I probably need to spend the money and ask someone I trust but I am just so frustrated with GM having 3 techs tell me I am imagining things and then two techs at an exhaust shop tell me the same. But I know my car and I know this is not normal and neither is the smell.