I have recently bought (within about a month) a 1998 S70 base model.

Ok, so on the new car, the idling was always a *teeny tiny teensy* bit rough (was eventually going to get to that) - after a day's trip to Atlanta (from Nashville) and back, something is wrong with the car!! The trip was this past Tuesday and yesterday night (Thursday), I noticed this.

There is a smell - never smelled it before anywhere, kinda like fireworks (after you shoot them off) mixed in with a mineral spirits/metallic smell. The funny thing is, I can't see smoke and it goes away once you turn the car off. (Why I think something is in the engine...) My boyfriend thinks it's my transmission (changing the fluid was on the to do list - it was very unmaintenenced by the previous owners...), but then if so why would my car idle so rough? It feels like I'm on a boat... seriously! I haven't checked the oil to see if it's a blown head gasket (the temperature gauge points perfectly in the middle when the engine warms up and the engine never over heated in the first place) - I am at work and am heading to my dad's (a 10 minutes drive) as soon as I get off.

Also, today on our way to work, it works fine with higher rpm, but when I let off the gas pedal to slow down and it felt like the engine was choking (like it needed spark plugs or something, except when you need spark plugs this usually happens when you push the gas and not let go, right?)

So, here is a list of what could have led to this: (or what I have gathered)

1. Tranny fluid/tranny itself

2. letting the gas tank get empty before I fill it (hey, I am in college... the guy at work said it could be dirty/bad fuel injectors)

3. bad timing belt? timing off (dealer exchanged at 75k, the car is 116k now, could it have gotten messed up with my #6 experience?)

4. throttle body hasn't been cleaned (on the to do list)

5. air pump is out; why the engine light is on and I confirmed this with the dealer (still haven't replaced that one 'cause I thought it could wait - maybe it's just fried itself completely, but wouldn't that smell after the engine was off and it wouldn't cause the engine to idle rough.... right?)

6. a small incident that I think may have led to this: (no woman jokes please) on our trip back from Atlanta, I stopped at a gas station, but on the off ramp to get there, I took a wrong turn and decided since no one was there I would back up and go the other way - well, as soon as I back up, there is this giant semi coming and I try to stop the car, throw it in drive (like in the good 'ol manual days, without thinking) and the car chokes out and dies (kinda like letting the clutch go while in gear) I restart the car and it is running rough, but then is fine. No problems until Thurs. ...did I throw off the timing? Why does it smell? Did I destory my car?

Someone from another forum said that it sounded like a catalytic converter going out. I hope this is not the case. Could a faulty air pump cause this? Or would the oxygen snsors go out? The car has 116k. Can you replace these items yourself if you are car savvy or is this a mechanic only repair?

Which brings me to the second entry: