exhuast smell coming from the air vent

recently I noticed an exhaust smell from the air vent specially when the car
is in idle or on park, seems good when running. What could be the cause of
this? exhaust leaking, engine burning oil, or any possible cause?

My car is a 1992 accord lx with 110k miles on it and has a good MPG about 30
for most highway driving.

Thanks for any clue!

 

exhaust leaking and the fumes getting to your heating system air intake

 

It's probably an exhaust leak. Since the smell is coming from the air
vents, I'd venture that the leak would be towards the front of the car and
is getting sucked into the air intake of the vents right in front of the
bottom of the windshield. The first place I'd check would be the exhaust
manifold. Check it for cracks or a bad seal. It could also be leaking
where the manifold connects to the pipe going under the car. Depending on
how cold it gets in your area, it might be a good idea to check the car for
leaks first thing the morning when it's still cold. Your exhaust fumes will
be more visible when it's cold because of the water vapour. Just poke your
head under the car when it's running and look for white smoke coming out
anywhere.

 

How about .... the car in front of you is a smoky car"
maybe you had your air vent on recirculate and now you have it drawing air from outside.

 

Yeah, that happens sometimes too but the original poster said he smells it
when the car is parked or idling. Of course, he never specified whether he
meant in his driveway or on the road so you could be right.

 

Thanks for all these inputs. I'll check the leaks as you mentioned. I don't
think the fumes come from other cars because this problem exits when in the
open parking lot or idles when no car is in front of mine.