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Thread: Idle Issues

  1. #1
    Jr. Apprentice
    Join Date
    Oct 2007
    Location
    Redding, CA
    Posts
    22

    Default Idle Issues

    Just want to know what you guys think the most common/first place to look would be. I have a 1993 K1500 Burb. It idles great when you first start it, but after driving for a while then driving around the parking lot when you let off the gas the idle will drop like it is going to die (it never does completely die) then comes right up where it should.

    From what I hear it could be, EGR Valve, MAP Sensor, Fuel Filter, or Fuel Pump. I don't mind replacing them all, but am trying to save a little money this month and need to take it on a little trip for Thanksgiving. So replacing the culprit the first try would be nice.


    TIA

    I am hoping its NOT the fuel pump DON'T want to drop the tank!!!

  2. #2

    Default

    The most common issue with bad idleing around here is vacumm issues, so you can start there. Unplugged frquently reccomends using a can of starter fluid and spraying starter fluid on different potential culprits. If the idle runs up when you hit a certain spot, you found it. Beware, using this method could potentially be dangerous, so be careful.
    Christopher

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half



    There are 10 kinds of people, those who understand binary, and those who dont...

    Remember kids, the only difference between screwing around and science is writing it down- Adam Savage

  3. #3

    Default

    I would kinda doubt the fuel pump but fuel filter is a possiblity. Crawdaddy is right its probably vacumn leak. Good luck



    Jamie

    2007 Ford E250(Work van) (Ya, Ya, shut up!)
    1996 GMC Sierra SLE 1500 5.7L/4L60E

  4. #4
    Jr. Apprentice
    Join Date
    Oct 2007
    Location
    Redding, CA
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    Default

    Not a vacuum leak tried that and nothing. Might try it again after it warms up more.

  5. #5
    Legend unplugged's Avatar
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    Sep 2006
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    High Deserts of SoCal
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    2,554

    Default

    How does the performance differ between neutral and drive? Could be something as simple as a bad plug or plug wires. I recently picked up an intermittent stumbling idle after some recent work. It idles rough in gear and smooths out in neutral. I'm thinking I have to go back over the plug change I just did, but haven't had the time.
    There is no way to happiness....happiness is the way.:yipi:
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    High Desert SoCal
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  6. #6
    Jr. Apprentice
    Join Date
    Oct 2007
    Location
    Redding, CA
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    Default

    I just replaced the wires, plugs, cap, and rotor. It did the same before and after. I am starting to think it is the fuel filter.

  7. #7
    Jr. Apprentice
    Join Date
    Oct 2007
    Location
    Redding, CA
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    Default

    Any new ideas? So far plugs, wires, cap, rotor, o2 sensor, fuel filter, and oil change. Still the same thing it will drop to like 100 rpm and idle all rough.

  8. #8

    Default

    You might want to try unpluging the IAC and MAP sensers when it is running rough. if theres a change in the idle u have most likely found your problem. It should kick in to default mode if u unplug either one for a short time.

  9. #9

    Default

    not to be an a$$ but have you checked the computer for codes? that be a good start. i just got a truck that a mechanic of 35 years told the customer the head gasket was junk and he wanted $2000 to fix it so they dumped the truck to me for free. i started it and the cat went to bright red on the pass side and it was boiling the heater hoses. i put the code reader on it and the ignition moduel failed it test. i replaced and all was good and i tried to give it back to the owner but they said it is yours and it is now going to the Youth group of our church for money for the group. sometime the computer will tell you wat is wrong (some times it does not but a good starting point)....mike
    Michael Collins
    1993 4X4 Suburban
    many other toys as well

  10. #10
    Jr. Apprentice
    Join Date
    Oct 2007
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    Redding, CA
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    Default

    Nope already tried it flashes 12 for no codes

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