One or two hundred fluctuation would seem ok in a 15 year old car but 500 to 2000 shows some sort of problem maybe an intake leak somewhere. If you can't find anything obvious try the "propane test". With the engine running and the fan wind blocked go over the intake system with a small propane tourch to see if the gas causes any increase in idle. I suppose I should mention UNLITE propane tourch. Was the throttle body removed when it was cleaned? The throttle linkage could be too tight or the throttle positon switch missadjusted or maybe the switch plug is loose. Usually the throttle body gasket can be reused unless it was torn up alot but that could be a leak source.