High Rev at start up

JEF · 03-18-2002, 06:46 PM

My idle is not less than 3k. When the engine is hot it can idle at 4-4.5k. I was told it could be the throttle position sensor ,the O2 sensor or idle regulator . Any help would be appreciated.

Rich · 03-18-2002, 08:01 PM

What vehicle, engine, etc?

We need more info.

JEF · 03-19-2002, 06:28 PM

Yeah , I noticed that after I already made the Post.
Anyway it's a '86 Tahoe S-10 4x4 2.8 EFI
130,000 miles . I bought it new in Downey California . It has been a reliable truck for 15 years but after 125,000 miles I had to replace the clutch ,at 130,000 miles,it was the main shaft ,3rd&4th gears of the manual tranny.Now I just have to figure out this High rev deal .
Thanks for the reply, Jef

Rich · 03-19-2002, 09:12 PM

4-4.5K

That is VERY extreme. Check the TPS, make sure nothing is sticking, try that. Next try unplugging the MAP sensor and starting up, see what happens there.

Are you getting an engine light? I think there is a way to pull the codes from it.

Its just a shot in the dark, but I had a friend with an 86 S-15 that had a similar problem and it turned out to be his MAP sensor gone bad.

It could also be the TPS, but I doubt an O2 would make the idle go that high.

Its just a shot in the dark, but I hope it helps.

JEF · 03-20-2002, 08:30 PM

HuMMer,
I am getting a "check gages" light but, that started a couple of months ago.I disconnected the battery . That didn't re-set the gauge, go figure? And my mechanic ran the tests . It came back a code 12 (which is normal) I will check the TPS as soon as it stops raining here in east central Ohio. And the MAP sensor.
I'll let you know what happens, thanks !
Jef

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