'92 350 -- idle hunting on hot start

I have a '92 C1500 truck with a 350 engine (146k miles). It starts fine and runs good on cold start. On a hot start, on drive off, the idle will hunt until I put the trans back in neutral. Then it will set at normal idle. It also will surge under light throttle while driving at road speed, but not all the time. I've changed the frame-mounted fuel filter and checked the EGR valve for a carbon chunk. There are no codes set. I'm sure that somebody out there has had a similar problem and can help me fix this. If you can point me to the most likely thing to look at, that would be great, and save me some time and trouble. Thanks.

get a can of wd-40 or carb cleaner and spray around the base of the throttle body as well as the intake and vacuum lines. if you find a spot that drasticly changes the way it runs you found the leak. it's pretty common for the left side of the throttle body base gasket to get sucked in a little and leak.

I'll check it, Thanks, Sevie

I'm pretty sure there's a TSB about that. I don't remember for sure, but I think it had something to do with the IAC motor.