engine mis
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engine mis
Hi All, I have a mis and spark knock an a 2001 f-150 4.6 cu. I changed plugs and fuel filter , checked fuel presure ( within specs) cleaned egr valve ,no carbon. check vacuum hoses , It idles good , but under normal driving it hesitates and knocks. if driving real easy its less. I've had lean burn on right and left bank ( po171 -po174). I've had five fill ups and added injector cleaner to them, with no change . a freind said to have a garage power flush the injectors , but I'm thinking they are clean ,because if I drive aggresive it seems to have power.Thanks to all. any Ideas
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Joined: Oct 2005
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From: Louisville, Kentucky
P0171 and P0174 are classic codes for a vacuum leak. Check the 90 degree rubber hose at the back of the intake manifold. You may also want to clean the MAF, especially if you have a K&N filter that you recently cleaned and re-oiled. Good luck!
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Joined: Nov 2001
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From: Duluth, MN
Clean the MAF............................................... .... I think there's even a TSB out on it. Unless thats only available to us Ford Techs. 
Monitor BARO pids with a scanner(not code reader). I know in northern MN the BARO should read about 155-156(not sure about other parts of the country). If it's lower then that try cleaning the MAF, clearing the KAM and driving it for a while. If the BARO still stays low, replace the MAF.
Monitor BARO pids with a scanner(not code reader). I know in northern MN the BARO should read about 155-156(not sure about other parts of the country). If it's lower then that try cleaning the MAF, clearing the KAM and driving it for a while. If the BARO still stays low, replace the MAF.
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Originally Posted by KingRanchMan02
P0171 and P0174 are classic codes for a vacuum leak. Check the 90 degree rubber hose at the back of the intake manifold. You may also want to clean the MAF, especially if you have a K&N filter that you recently cleaned and re-oiled. Good luck!
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Originally Posted by Wilber15
Clean the MAF............................................... .... I think there's even a TSB out on it. Unless thats only available to us Ford Techs.
Monitor BARO pids with a scanner(not code reader). I know in northern MN the BARO should read about 155-156(not sure about other parts of the country). If it's lower then that try cleaning the MAF, clearing the KAM and driving it for a while. If the BARO still stays low, replace the MAF.
Monitor BARO pids with a scanner(not code reader). I know in northern MN the BARO should read about 155-156(not sure about other parts of the country). If it's lower then that try cleaning the MAF, clearing the KAM and driving it for a while. If the BARO still stays low, replace the MAF.
I used a code reader, I cleaned the maf and drove . Did not clear the kam ???, this must be dealer repair stuff . I tryed to find more info on the TSB for this but could not ,other than the code numbers. thanks
Last edited by stategame; Dec 23, 2007 at 06:18 PM.
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