I have a 1998 Toyota 4Runner. After doing a full throttle body cleaning (including the IAC), my warm idle was at >2000 rpm. It seems that cleaning out the extra carbon probably allowed more airflow than before for any given throttle position, and also that the clearances in the throttle body has probably loosened over time.
After some fiddling around, I ended up adding a small return spring to force the throttle body close better. This helped with lowering the idle down to normal (700 rpm) but the disadvantage is that it makes the throttle feel heavy.
Gradually over a few days, I was albe to slowly loosen up this return spring tension more and more until I was able to remove it completely. It seems there must be some gradual relearning process that the ECU does to control the IAC (idle air control) valve to maintain idle. There is no idle set screw and pulling power to reset the ECU does not appear to affect the idle.
My idle rpm is now 1000 with the makeshift return spring removed. Normal idle should be 700. Does anyone know how the ECU relearns the idle? Does this just take alot of idling or is there some way to force it?
After some fiddling around, I ended up adding a small return spring to force the throttle body close better. This helped with lowering the idle down to normal (700 rpm) but the disadvantage is that it makes the throttle feel heavy.
Gradually over a few days, I was albe to slowly loosen up this return spring tension more and more until I was able to remove it completely. It seems there must be some gradual relearning process that the ECU does to control the IAC (idle air control) valve to maintain idle. There is no idle set screw and pulling power to reset the ECU does not appear to affect the idle.
My idle rpm is now 1000 with the makeshift return spring removed. Normal idle should be 700. Does anyone know how the ECU relearns the idle? Does this just take alot of idling or is there some way to force it?
