Originally Posted by yodasfro
A bad ISV (idle stabilizer valve) can cause this. Try remove it and cleaning it with WD-40.
There is also an ISV control unit it's a double wide relay in the relay panel behind the drivers knee bolster. Try giggling it a little or remove and plug it back in.
Thanks a million! I cleaned out the ISV but no luck, ended up finding one for 35$, just installed that and the 5000 is purring like a kitten, and not screeching like a 5 cylinder at 3000 revs.