My 91rs 3.1 has new welded exhaust from manifold back, new weather stripp on doors and hatch, and I'm still getting this Oder/fumes inside.It leaves a odd taste in the mouth as well as faint odor(not rotten eggs)
Vent set on warm or cool, does not help.Fan on or off, does not help.
Can anyone tell me where/how fresh air comes from because i dont think im getting any.
I also notice a slight heahach sometimes after 40-50 minute drive.
Also ac not working if that helps.

 

have you or someone else removed the seal from the rear of the hood ? it seals eng. bay fumes from entering vents at base of windsheild . re-install it and i think your problem will be solved . good luck .

 

I hate to be stupid but is this like a door weather strip.The hood has been changed by previous owner and im not sure what to look for.

 

open hood , look across rear of hood , if it has not been removed you will see it . it should be where the hood rests on top of firewall in front of vents & wipers . good luck .