Toyota Repair: rpm fluctuation 1990 camry, vacuum leak, air leaks

Question
My 1990 Camry has had a problem with the rpm's fluctuate after engine has warmed up. It doesn't do it when driving. I noticed it 1st when I took it to get smogged and it failed the test. I have cleaned the Throttle body (and it was pretty dirty) and the air flow tube leading from the air-cleaner and it still does it. I don't have any engine warning lights or anything like that. Runs fine just need to get it smogged. The engine has 300K.
Thank you for your time and we appreciate any help we can get.
D & D Miller


Answer
Idle fluctuations are normally caused by an intake leak or vacuum leak on the intake side of the engine.
This could also be caused by a cylinder misfire or low compression in one or more of the cylinders, did you check the air intake tube for any cracks or loose clamps?
Any air leaks there will cause this problem.