Whatever it is, it does not seem to be uncommon. My freshly rebuilt '93 does the same darn thing. <img src="/forums/images/graemlins/angry.gif" alt="" /> I don't have much history with the truck since we bought it needing a timing chain (and as it turns out a complete overhaul) so I don't know the onset. I do know I replaced a TB gasket for a vacuum leak (wrong shape to the gasket) which of course made a WORLD of difference, but didn't address the underlying issue.

I would try the A/C suggestions, except the only A/C I have is in a box on my garage floor, where I bought it from a junkyard! <img src="/forums/images/graemlins/lol.gif" alt="" />

Oh yeah, and except for idle the truck runs really well with Ted's head, valves and cam.