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2003 Ford F-150 Question: I have a bad idle and surging problem after it warms up.

 

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Sdd, 5.4L V8, Spokane, WA, March 31, 2014, 11:58
 Rookie

If I un plug the MAF it seems to clear up. Replaced MAF about 500 miles back. Replacing TPS and have replaced Vac sensors on EGR AND CANISTER vent valve.

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  • Answer #1

    March 31, 2014, 14:45
     Journeyman

    Did you check if there's any vacuum leak somewhere?

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    Sdd, March 31, 2014, 15:02
     Rookie

    should have been 5000 miles, I'm checking on a smoke test to check for vacuum leak. Seems you can't do it with spray as the PCM will try to compensate it.

    I don't know the system well enough to understand why unplugging the MAF would fix the problem.

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    Action702, March 31, 2014, 15:18
     Journeyman

    If there's any vacuum leak after your maf sensor it will act up

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    Sdd, April 01, 2014, 11:48
     Rookie

    I think your right on with the vacuum leak. I changed the TPS and drove for 40 minutes and no problem. I did get a rich burn code, cleared it and it did not come back. Will replace problem PCV hose on back of intake and drive again. Hope this is the vacuum problem.

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