Start the car, idle is way too high?? v.helpmeplz

Discussion in 'OT Driven' started by Jas0n, Dec 20, 2006.

  1. Jas0n

    Jas0n Антихрист

    Oct 8, 2005
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    Right, here's the situation. I drive a 1999 Pontiac Grand Am GT. This comes with the 3400 and a four-speed automatic transmission. The car is just a few feet from turning over its first 100,000 miles. Here's the problem.

    Sometimes when I start the car, the idle is significantly higher than it should be. Normally when I turn her on she idles at just under 1000 rpm, and if she's warm, that'll be lower ... say 600-800 rpm. A few times this last week or so, I've turned her over and she idles at maybe 1500-2000 rpm. The idle engine speed increases as I let her sit! If I get into gear, the car drives just fine, but sometimes staying stopped is difficult -- like being in drive and giving the car so much gas, of course. Also, shifting (as in, going into drive, neutral, reverse, park) seems like a bad idea as well. In neutral and park, the rpms shoot up to whatever the idle has been established as, and I'm afraid I'll dump my transmission trying to switch into a go gear with the engine revved up like that.

    Every time that this has happened, I have let the car run for a moment, turned it off, turned it back on after just a moment (minute or two, tops?), and it idles just as it should. This method of correcting the problem has not failed yet, but it is obviously just a band-aid when I may very well have a broken bone to mend.

    A few notes on maintenance and repairs: I think I'm a little bit behind on my oil changes, though I don't see how that could matter. Nearly every mile I drive is on the highway, and it isn't like I've gone ten thousand miles since my last lube job. Earlier in the fall I had to replace a water pump, as my old one had a slow leak. I had staved off replacement by adding coolant, but of course eventually that method went bankrupt and I had to get the part taken care of. I probably made the wrong choice, but in order to save money, I opted for a remanufactured piece, which is now leaking again, I think... very slowly. I say this because I lose coolant far faster than I should, and have yet to see any signs of a leak anywhere else. (And the original water pump failing was, of course, unmistakeable.) I have changed both of the front wheel bearings. This time last year I had the accessory belt changed. I think my timing is handled by chain, but am not positive. One of my rims is ever-so -slightly bent somehow. It holds air just fine, but it doesn't hold a balance particularly well. She's been in no significant wrecks, generally baby the car when I drive, and have made absolutely no modifications to the vehicle.

    Thanks, experts. :)
  2. James May

    James May Active Member

    Jun 14, 2006
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    480 AZ
    perhaps the idle control soleniod, or an ECM issue, does the car have a check engine light?
    - intake hose leaking/cracked
    - bad maf sensor?
  3. MeanGreen

    MeanGreen Active Member

    Sep 7, 2006
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    Annapolis, MD
  4. CastorTroy

    CastorTroy New Member

    Jul 1, 2005
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    Anytown, USA
    Idle air control motor or the MAF sensor (and related wiring of both) are the first things I'd check. These two things are the big two common culprits of idle problems.

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