Cold Start "jumping" Idle Speeds


92 Mit Eclipse 2liter non-turbo. On cold starts, idle starts high (at 2k instead of normal 1200-1500) then begins to rapidly drop and rise about 300 rpm until engine begins to warm (about five minutes), then idle works nominally. Idle speed control motor tests OK and functions correctly when engine warm. Good O2 sensor, new coolant temp sensor. When idle is jumping up and down, if I remove wire from idle position switch (it tells computer when accelerator is NOT being depressed) the wandering stops. Any ideas, suggestions? Thanks.


Replace the switch.



I failed to ssy in the original post that I tested the idle position switch and it is working properly. Any other suggestions?