Just bought one. This is the first vehicle I ever sought out because I wanted it. No older, due to inherent higher miles, and no newer as I don't like the style change. Anyway, in spite of the crappy gas mileage of the 4.7 l engine, I love it, but every now and then I get this funky sour exhaust(?) odor inside. It seems to coincide with opening or changing a vent setting especially with the AC. I.E. Turn on the AC and turn fan on high speed. I can't hear or see any exhaust leaks underneath and I'm not even absolutely sure that's what I smell. It generally goes away when I turn the fan down or change the vent settings or open the windows. I've driven it long enough to feel its not making me immediately sick...I don't think.... (wife often tells me I'm sick, but different story ) however, it is annoying. Thoughts, anyone else have similar issues on these trucks?

Thanks,
Scott

i have an 04 with a 5.7, it has a small exhaust leak at the drivers side rear cylinder. i get a strange exhaust smell too with the fan on sometimes. its faint and goes away pretty quick, so ive just ignored it.

Thanks NEVjr. Thats kinda what I've been doing for now