Won't idle when first started. I live in warm weather, about 80-90 degrees. The RPM's are at about 400-500 and the engine almost stalls, unless I keep my foot on the pedal. Within 30-45 seconds of giving it a little gas, it idles normal. If I turn the engine off and restart it when its warm, it idles fine. I have adjusted the throttle position switch, which was not being activated with the throttle was closed. (WOT was adjusted fine) This didn't solve the problem. Any ideas?

 

sticky idle control valve? or a throttle idle switch thats not working reliably when cold. the IAC is only activated when the throttle idle switch is closed...

it should be idling at abouyt 1000-1200 rpm for a few seconds at leasst after starting, then drop down to the nominal 750 RPM.

400-500 is about where it idles when the IAC is disabled/unplugged and all accessories are shut off, and at this low unregulated idle, its prone to stalling. it would also do this if the IAC was 'stuck' closed, or that throttle position switch is open.

 

Thank You. I will remove and try to clean the IAC. I guess a good test would be to unplug the IAC and see if anything changes. Maybe even short the contact of the idle switch. I was not aware of their relationship with each other. When warmed up, I did notice my engine idles a little high.. about 900 RPM's, and what I think is the idle screw, is backed all the way out and not even touching. The throttle cable has plenty of play.

 

Your problem is likely caused by the Coolant Temp Sensor, the one under the third rail of the intake manifold. Your idle is fine after the engine warms up...

 

lev has a point there, but 30 seconds or whatever is hardly adequate time for the coolant to warm up.

re: idle air screw, a LH 2.4 system doesn't have one, LH 2.2 (up to 1988) did, the procedure was, after everything else is dialed in and working, disconnect the IAC and adjust the idle to 500 or so with the screw, then plug it back in.

note, if you remove the IAC, good chance the 25+ year old rubber hoses connecting it will crack and fail, have new hoses handy for the re-install. *any* tiny air leak there will mess your idle way up.