High idle

[nameskreen]

I have a 97 Mountaineer 5.0 with 260k miles. When the truck is at operating temperature and I shut it off for a few minutes (to go into a store for example) when I restart it the idle is high (about 2200 rpm) When it first happened I checked the coolant temp with my scanner and it was correct. I put it in gear and drove and the idle eventually dropped after about a minute I cleaned the IAC and it went away for a few days but now it's back. It did it this morning, so I shut it off, unplugged the IAC and restarted it. The idle was very low, I plugged it back in while still running and the idle returned to normal. Not really sure where to look. IAC? TPS? Thanks

 

[J_C]

When I clean my IAC, I prop it up on end and put a drop of light oil on the shaft at the bushing to run down into the bushing for a few hours.

idle RPMs up & down

2000 v8 ~200k miles. recently replaced plugs & wires; rebuilt injectors. This has only happened a few times over the last 2-3 months or so; all after the above repairs. In the morning sitting in the driveway warming up for the day the RPMs go up and down; ~ 500 to 1,500; no change w/ AC, heat...

www.explorerforum.com

If that doesn't help, your IAC may be too worn out to reuse. It might instead be a vac leak elsewhere, I'd look at live data on a scan tool, long term fuel trim, and I doubt it's the TPS but that reading should also show up in live data.

 

[nameskreen]

Thanks. I did check the fuel trims, they look good. It's strange that it only does it when it's only been shut off for several minutes. And it doesn't always do it