1997 Yukon revs then dies when in park

[dollarbillHCCA]

I have a 1997 2 door Yukon with a 350. When the engine is hot (after driving a bit), the engine will rev up several times then die when I put it in park. This never happens when it is in gear (in drive, idling with foot on brake) only when it is in park or very rarely when I first put it in gear. I can keep it from dying by pressing the gas, but as soon as I let off it will die.

Other symptoms that are probably unrelated deal with the transmission. It sometimes won't shift into overdrive, but the next time I start it it will shift into overdrive.

Thanks for the advice!!