Idle problems

[geauxbear]

Ok I had to replace my ecu and now it is working properly. I have a 1990 geo tracker 8v automatic 4x4 and it idles at about 2000 rpms even after running for approximately 5 to 6 minutes. When I put in gear it will drop down but not sure what the cause is. I am not sure if the previous owner adjusted anything that would make the idle that high. Any advice would be greatly appreciated. Oh yeah there are no codes stored on the ecu.

[jtgh]

hello 90'-8v.
high idle is cause by:
air leaks.

CLICK >>
racings


I then, after being confident all is well, I do the factory Idle setting procedure.
holler if need it. (takes a voltmeter)
if not you can just guess.

cheers.

[geauxbear]

Ok, once engine runs for few minutes it idles down but will race between 800 and 1200 rpms, speeding up and down (racing). Should I try to adjust or go in a different direction. If I do need to adjust not even sure what to do very new to this mechanical stuff . Any help appreciated