High idle upon start-up regardless of cold or hot starts | Ford Explorer - Ford Ranger Forums - Serious Explorations

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High idle upon start-up regardless of cold or hot starts

///Manuel

Active Member
Joined
December 12, 2002
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City, State
Denver, CO
Year, Model & Trim Level
92 XLT
When I start the car, the idle raises up to 2k then slowly decreases to 750 rpm's after a minute or so.
I swear that it wasn't revving so high in the past. When warm it goes to about 1.8k maybe a touch lower.
When I disconnect the idle actuator, there's no such surging anymore.

I checked the pcm engine coolant temp sensor resistance but I'm not sure about its specs.
It seems to be working (increasing resistance with the decreasing of the temperature).

Everything else seems to be functioning properly (IAC, MAF, air filter, no vacuum leaks, TPS, CPS, O2, no codes).

--
Manuel
 




Jason94sport

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April 30, 2001
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FL
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02 Sport 2WD 5 speed
Likely a bad TPS on the throttle body. Replace it. It will not show any code if it has an issue.
Take the IAC off & clean it as well.
 




///Manuel

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92 XLT
But the TPS checks out ok, voltage-wise, I get 4.61V full throttle and .8 to 1.1V depending on my adjustment at idle (neither seemed to make a difference).
I swapped the IAC with my old one, same exact behavior.
 




///Manuel

Active Member
Joined
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Messages
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City, State
Denver, CO
Year, Model & Trim Level
92 XLT
Also, I started the car with the tps disconnected and got the same behavior as well as a check engine light.

I need to find out the specs for the coolant sensor. It's the most likely culprit I believe, or maybe I could just swap it anyway.
 




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