Has anyone actually fixed the high start idle problem on their 80?

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Central Scrutinizer
Jan 26, 2004
Air Mobile
I have searched through a plethora of threads and from what I can find of all the high start idle threads, nobody seems to have had a definate fix for the problem. I have been chasing this for a while on mine. Starts at 2-2.1k even when warm, then drops to ~650 after a few seconds. I have checked the following IAW the FSM. Throttle linkage (even does it without the cables connected to the throttle or cruise) ECT switch and wiring, IAC valve. I have not replaced the ECU and I hope that isn't the problem. I am going to swap ECUs between mine and a buddies 94 to see if the problem switches trucks to rule the ecu in/out.

I remember reading a page where users adjusted their IAC valve to only allow it to open partially. I don't think it was on Mud though... let me see if I can find it.
I was doing that. I think it is like a band aid on a sucking chest wound though.

I'd really rather fix the underlying issue.
My wife finds it annoying. I'd love to find a fix just to shut her up.

(fixes to permanently shut her up have already been considered, thanks in advance, though)

I did the O-ring trick (search "O-ring trick") on the TPS about 2 years ago and my start-up idle went from 1600 down to 1200 until warm up then drops to about 600. A few weeks ago while replacing the valve cover gasket, I had the throttle body and MAF and all that stuff cleaned real good. Ever since then my start up is 800 and drops to 600 when warm. I might remove that extra o-ring now and see where start-up is after all that cleaning.
Mine does it too, thought it was just the nature of the beast.
I hope that the cleaning has helped - and run Seafoam thru it has been a common reply about the high / extended cold idle issue. I still have trouble relating cleaning passages to temp or resetting by pulling the battery connection. These are the only two things that I've seen change the problem so far. Just wondering so far; I haven't taken coolant temp sensor resistance measurements yet - maybe this coming weekend.

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