1998 Chevy K2500 7.4L 167k miles.

That was a direct quote from earlier today. I was showing a friend my sound system because he is looking into getting one, and I had my truck running so my amp didn't kill my battery. After sitting there idling for a few minutes, we began to smell a terrible odor. It smelled like rotten eggs, with a rather large hint of something I can't quite put my mind on. I got out of the truck and sniffed the drivers side exhaust pipe [true duals] (which isn't advisable, but I did it anyway), and it smelled normal. I then sniffed the passenger side exhaust pipe, and the putridity blew me away.

We also noticed a small amount of smoke on the passenger side exhaust, but to see it we had to sort of look up the pipe. My friend said that it smoked more when I revved it up, and it seemed to come out in a poof of sorts, but I didn't witness this as it wasn't visible from the drivers seat.

There's no check engine light or anything either.

Does anyone know what this putrid odor (and other symptoms) could be caused by?

 

Hi Blindsight,

How are you doing today.

Sometimes the rotten egg small is from unburned emissions.

Now, everything else here is pure conjecture, but possibly a loose manifold donut is allowing exhaust fumes by your passenger side exhaust?