Hi irregular idle 22RE

91 Toyota 4wd truck manual 5 speed 22RE. Engine starts fine. Cold engine will have high idle as it should but instead of slowing down as the engine warms the RPM runs at 2000 and momentairly drops off and back up to 2000. This happens in shorter frequency (once a second) when the engine is warm. It can be driven but everytime I shift the engine RPM keeps going from 1500 to 2000. I replaced the coolant temperature sensor to the ECM. I cleaned the inside of the throttle valve. I did an electrical test of the TPS and Air intake sensor. I checked connections on ECM. I looked for vacuum leaks. I disconnected the cold start timer. using the service manual I checked voltages on the ECM terminals, all within specs. I replaced the ECM.
Found nothing wrong, can't seem to change anything and don't know what else to try.:mad:

Thats just a simple problem sir, May i know the history of your car? I can suggest that maybe it is in need of tune up. Maybe its just the clearance of your valve.:biggrin:

I have the same problem except when my truck is at a high rpm it does fine but when i brake it starts dropping , when i let go the brake it starts to get higher, close to 3000 rpm, someone help me please.

I have the same problem except when my truck is at a high rpm it does fine but when i brake it starts dropping , when i let go the brake it starts to get higher, close to 3000 rpm, someone help me please.

Brake booster or that big vacuum going to it might be leaking air. Try plugging the vacuum line and see if idle changes. I've heard this is a common reason for high idle in Toyotas. You could let us know what fixes it,,,,