Toyota Repair: 2000 camry le 4cyl idle problem, fe engine, private shop

Question
I have a 2000 camry le 4cyl. When the engine is warm, I crank up the engine and it rolls between
500-1000 rpm the needle just jumps. I've taken to two dealers and a private
shop. The dealer replaced $2,000 worth of parts (including reg. maint) they
still can't find the culprit. Their is no lights on in the dash but it is
increasing in frequentcy. The car is still under warranty and I would like it fixed before it runs out, What could be wrong?
Thanks

Answer
A common idle problem on camrys is the idle speed control valve located on the throttle body, you did not specify what parts were already replaced so if that was not replaced I would recommend doing so, it's sometimes referred to as an IAC valve also.
This is providing that it has the 5SF-E engine, according to the manual this should be the case, if it is a late 2000 model it may have the 3AZ-FE engine in which case the above does not apply.