Another case of chasing the weird smell... (propane, rotten eggs)
 

I recently noticed a weird smell inside my car, kinda like propare gas (rotten eggs) but very faint. I saw a lot of posts about this but my situation is a bit tricky and I figured it could help others if I wrote down a summary of it all, and some of you might help me pinpoint my issue.

What I noticed:
I can smell it when I get in the car or when I drive it hard, like after a good 1st and 2nd gear redline run. I can smell it inside the car or underneath, but doesn't look like it's coming from the tailpipes or the air vents inside.... nor the shift boot.

Using the search button, I found the following probable causes:
- mildew in the air vents
- seals leaking coolant, say goodbye to engine
- failing CAT
- transmission fluid spill
- new exhaust protective coating burning off
- dead battery overheating/overcharging and leaking acid

I'm ruling out:
- mildew, smell ain't from the air vents
- seals leaking since there's no white smoke, smell not from the tailpipes.
- failing CAT because it passed the recall test (for what it's worth) and I guess the smell would come from the tailpipes too.

Now here's where it gets tricky... the car has been in winter storage for 10 weeks, had it back for a week now.:
- trans fluid was changed at the same time as oil change when the car got out
- I had an MS dual catback installed the same day
- battery was drained and stayed uncharged for 10 weeks.

I looked at the battery and even though it wasn't spitting acid and fumes, I changed it. It really wasn't taken care of properly sitting uncharged for 10 weeks (my bad), it's from the 1st owner so I don't know how it was cared for before, it was very hot as if overheating (hotter than the engine after 20min of cooldown) and you could see that since it had been back in the car it had leaked from the negative pole.

I guess now my only option is to wait it out and see if it goes away after a while, but I'll never know if it's the exhaust or some trans fluid.

Any of you have an idea of how the "it smells when I drive it hard or when I get in the car" can be tied up to this?

It the gas you bought going bad.

dead animal?

I can't know w/o smelling i, but ym family has owned 2 Toyotas and they both siffered from the same rotten egg smell symptom. I believe its cause by a processin the catalytic converter. It a by-product of one of the reactions required to lower the emissions. In the toyotas' cases they were both ULEV vehicles, in the mazda's its just necessary to get by.
I picked up my 8 a day ago and within the first hour of driving it noticed the same smell......
Anyways, just my two cents.

I occasionally have the same problem. The thing that makes the most since to me is it's the smell of fuel in the cat from running rich. Mine usually only happens after I've run the car hard and then drive very slowly or stop.

There's your answer. Didn't you see the gear oil smell thread where everyone have the same problem?

Another possibility is sulfur content of the gasoline, per this TSB:

http://www.finishlineperformance.com...43-06-1678.pdf