High and Low idle

[eggiealta]

Hi, my dad has a 1990 Toyota Pickup 4x4 4cyl. Every time we drive it in the mornings it idles high, but when we press the brake to stop at a stop light or stop sign, it idles high and low very fast. Once it warms up good, then it stops idling high and low. we have change multiple sensors on the engine block, thinking it could be a temperature sensor but it didnt work. if anyone can Help i would really appreciate it.

Thanks

[fourwd1]

The reason it fluctuates like that is due to the idle being too high.
Once you cure the high idle problem, the fluctuations will go away.

Have you checked the ECM for any error codes?

You may want to look at the Cold Start Injector, CSI Timer circuit, even the coolant level.

[elrana]

This is an age old problem in the 22RE which I have seen addressed in this forum before; conclusion being that what was needed to address the issue was a new Idle Air Control Unit. I recently ordered one and even after installation the problem persists, only with a new twist that my engines' operatiing temp is now higher up to the point that i can percieve the difference in the cab. I dunno....any new suggestions???