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Super high idle

94 Lumina 3.1 MPFI. Yesterday I noticed the idle was high (1,500 rpm ) when I first started it. After the engine warmed it was OK. Today I go out to start it and the idle shoots to 3,000 rpm. I let it warm up but it does not go down to normal until I turn it off and restart it. I should also mention that today was much colder than yesterday. I don't have any check engine light on. Can someone tell me what I need to check out ? I don't have a scanner but I have a DVM. Thank you for any info.
Reply to
TOLYN9
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My 87 Cougar had a TAB (throttle air bypass) that was a valve controlled by the computer to adjust idle. On the Ford, it was up near the throttle plates on the outside of the throttle assembly. Mine had gummed up and cold weather made it stick more. Took it off and cleaned with carb cleaner and that fixed it.

Another thing that will cause high idle is a vacuum leak, but I doubt it would change by turning the motor off and back on unless there is some vacuum actuated device that doesn't always turn on (maybe you moved some AC or heater settings between startups)

good luck, bb

TOLYN9 wrote:

Reply to
bobby

Thanks for the info. I suspected sometrhing sticking. I have yet to get a book for this engine so I am kinda in the dark. Oddly enough, the problem didn't happen today. It was alittle warmer outside. I need to break down and find an affordable OBDII scanner. If anyone has any ideas, I am in the market to buy one. Thanks again

Reply to
TOLYN9

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