My 89 350,std trans. idles high, any ideas on the cause? it has no codes I changed the TPS and it helped some. Any ideas on what to check next? this is a shot bed step side it also leaks water to the passenger floor board when it rains. Replacing the windshield did not change it and it is not antifreeze any help on that one.

If it's throttle body injection it could be the gasket. Mine got sucked down with high revs and caused a vacuum leak thus high idle.

Thanks for the reply, I put a new gasket under the throttle body and it did not change the idle. I was wondering if the shaft the butterflies rotate on could be sucking air?

Could be leaking there. Try to plug it with a rag or something while it's running.Check for a vacuum leak somewhere, sounds like you have one.
EGR,intake manifold,leaky vacuum hose, etc.