Very high idle at startup
I have a 1992 F150 4.9 l. Everytime I start her up
she revs high and then backs down in approx. 5
seconds. We've checked or changed everything as
far as sensors. Cleaned valves and butterflies.
What might be going on? Help!!
5 Answers
Yea, I've had it for 5 years. This revving just started 2 weeks ago. Other than that it runs great and idles fine. Whatever is happening, is stopping it from throwing a code. We've cleaned and changed out sensors but rev still there. I'm thinking vacuum leak somewhere.
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Julio80211 answered 6 years ago
Did you find out what the problem was?? That's the same issue with my truck?
5 people found this helpful.
a bad throttle position sensor does this - should 1 volt at idle and go up with throttle
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