I experienced a similar issue with two camry’s, mine and my cousin’s. We also replaced the tps sensor and that didn’t help. It’s something called the idle control valve? I’m not 100% sure what it’s called, but my younger brother who is a mechanic fixed it. All he did was clean it with carburetor cleaner.
I was about to type a description of the solution, but I found a good one on the Edmund forums. http://townhall-talk.
edmunds.com/WebX?14@@.ef0c570!make=Toyota
The IAC or Intake Air Control Valve controls the engine speed at idle. It is controlled by the ECM.
Remove the rubber air intake (2) hoses at the throttle body and look inside the body. the tube on the right side has the IAC valve opening for air flow to bypass the throttle blades at idle.
It took me about an hour and half to disconnect and clean the IAC.
I disconnected the negative battery cable
removed the air filter
removed the connectors from the IAC and the throttle position sensor
I had to remove some black hoses from underneath the throttle body and on top of the air cleaner box get clearance that I would need later when I unbolted the throttle body from the intake manifold.
Remove the (3) bolts (2) on top and (1) on the bottom .
Also remove a screw from the firewall side of the throttle body to release it from the engine.
Turn the throttle body to remove the (4) phillips head screws.
There is a rubber gasket underneath, Because engine coolant does circulate through the valve, you only loose about a tablespoon of coolant. I did reuse the rubber gasket.
After you inspect it remove the electrical connector (2) screws carefully pull it away from the IAC.
Look for signs of carbon or scoring on the shaft that rotates also check the operation of the little door openning under the shaft, it opens and closes.
Mine didn't rotate freely and was dirty.(NOTE: the shaft only rotates enough to open and close the door beneath it.
I used a toothbrush and carb cleaner to free it up , the spray will empty out of the opening on the bottom.
It not difficult but there is never enough room to work under the hood.
Before you remove stuff , you have to check if there is a wire attached to it.
If you have a problem with your idle you might try spraying some carb cleaner through the opening in the throttle down to the IAC.
courtesy of Paul.