barry92sc

My 1992 SC400 just started this. When cranked from cold start it "revs" on its own. Like you are giving it gas but all by itself. After the car runs for about 10 minutes it goes away and runs fine. Any ideas what might be causing this or suggestions on how to fix it? I cleaned the throttle body but did not help. Maybe clean the AICV? Checked vacum hoses too but didn't see anything.
This all started after I had the oil and trans fluid changed. Don't think that would have anything to do with it but looking for any suggestions. Thanks for any help.