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4.6L Engine Problems Galore!

Discussion in 'Stock 2002 - 2005 Explorers' started by DavidS, October 25, 2007.

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    1. DavidS

      DavidS Member

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      City, State:
      Kingsport, TN
      Year and Model:
      '02 Eddie Bauer
      Suddenly last week, my 2002 Explorer EB 4.6L V8 started running terribly while stopped at a drive thru window. The "service engine soon" light came on. At idle it surges wildly with rpm's bouncing from 600-1200 and acting like it's going to die. It causes the whole vehicle to quiver badly and you can tell it even under way if the rpm's are in the 1000-1500 rpm range. When you come to a stop, the rpm's try to stay around 1000 rpm's until you've stopped then it starts surging up and down again. I took it to Autozone to have it scanned and it showed a bunch of codes:
      ----------------------------------
      P0171: Fuel Trim Bank One condition, O2 sensor recognizes a rich or lean condition on one engine bank only.

      Probable causes
      1. If banks one and two together suspect fuel pressure or MAF Sensor.
      2. O2 sensor defective
      3. Iginition misfire-repair
      4. Fuel injectior problem

      P0174: Fuel Trim Bank Two condition.

      Probable causes: same as above with addition of Failed HO2S21.

      P0300: Cylinder misfire detected-random cylinders.

      Probable causes:
      1. Ignition system fault
      2. Vacuum leak
      3. Injector fault
      4. High or low fuel pressure

      P0316: Crank Sensor condition

      Probable causes:
      1. Crank sensor defective
      2. check connector & wiring to sensor
      3. Check trigger wheel for damage

      P1131: Lack of bank 1 O2 transitions-lean

      Probable causes:
      1. Misfire on bank 1
      2. Vacuum leak affective bank 1 only
      3. Fuel injector problem bank 1
      4. Engine mechanical condition

      P1151: Lack of O2 switches Bank 2 sensor 1, ECM couldn't adjust fuel trim of a lean or rich conditon.

      Probable causes:
      1. Fuel pressure high or low
      2. MAF sensore dirty/defective
      3. Vacuum leak on engine
      4. Leaking fuel injector or fuel pressure regulator
      -----------------------------------------------
      Has anyone had anything like this happen to them before? I'm going to clean the MAF Sensor but I can't imagine it causing all this. It's strange that all this started all at once. Do O2 sensors suddenly fail, especially together like this? Any help would be appreciated as my dealer charges a minimum of $100 just to check it out and then the parts and labor for repair. I'd like to do it myself if possible. Thanks to all!
       
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    3. wchain

      wchain Member

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      City, State:
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      Year and Model:
      02 XLT V8 2WD
      Check your PCV hoses for the P0171/0174. Lean in both banks usually yields a large vacuum leak of some sort.

      1131/1151 are related probably to the vacuum leak. Again, check your PCV valve and hose assy. You'll need a 1/4"driver to remove the big engine cover to access the PCV hose.

      Good luck.
       
    4. DavidS

      DavidS Member

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      Year and Model:
      '02 Eddie Bauer
      A vacuum leak it was although not in the PCV valve line. It was in a small 1/2" 90° hose right on top of the intake manifold that was pulling from the intake air and was completely rotten. It was a bear to remove it in several pieces. What it's purpose is I don't know but replacing the hose fixed it. I also cleaned the MAF Sensor while I was in there. The "service engine soon" light is still on even though it now runs fine. How do I go about resetting that light?
       
    5. JDraper

      JDraper Somewhat Functional Moderator Emeritus

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      City, State:
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      Year and Model:
      '11 XLT
      To re-set the computer, disconnect the battery for a few minutes. That will clear all the codes.
       
    6. shibbz

      shibbz New Member

      Joined:
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      City, State:
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      Year and Model:
      02 EB
      My explorer has the exact same issue.. the 90 degree right angle hose.

      I've been looking for a replacement.. I just want to replace the elbow and not the entire part - where did you find this elbow?

      Was it truly 1/2" Mine looked 5/8" but it was late and I was tired.

      Thanks
       
    7. Cgy04XLT

      Cgy04XLT New Member

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      City, State:
      Calgary,Alberta
      Year and Model:
      04 XLT
    8. Beausdad

      Beausdad Member

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      City, State:
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      Year and Model:
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      the fix

      I had the same problem. I went to NAPA and they had a hard plastic elbow that I attached about a 2 inch piece of 5/8 fuel line on either end and fixed the running bad.

      Service Engine Light will not go off by unhooking negative battery cable on
      3rd gen. You must go to someone to get it shutoff. That is what I was told.

      Auto Zone said my MAF and O2 Sensors were the problem. It was actually that elbow. I cleaned the MAF using almost a whole can of MAF cleaner - side note MAF cleaner is the same as brake parts cleaner. I had my light shut off. Drove home. Turned Ex off. Came out next morning. turned Ex on. Light came back on. Now I have to replace O2 Sensors. Only problem. Damn thing has like 4 of the damn things.

      Remember the good old days when all you had was a block, Carbueretor, master cylinder, battery and a transmission. TECHNOLOGY SUCKS!!!!!!!!!!!
       
    9. corsair1987

      corsair1987 New Member

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      City, State:
      las flores ca
      Year and Model:
      2005 Ford Explorer xlt
      Please read!!! I need help with my '05 Explorer, engine die's... still :(

      2005 Ford Explorer v6 4.0 111,000k

      A few weeks ago, I tried to start my Ford, the engine would turn over, then it would die.... so I took it in to the Ford dealership, they did all there checks and found out that the throttle body was bad, so they replaced it... When I drove it home the "gas pedal wouldnt accelerate, then the power steering seized, I turned the truck off and turned it back on, and it worked.. Later that night I tried to start my Ford, then my engine sounded odd, then the "service engine" light came on, then it died.... when I turn the truck on, now it dosnt even turn over...... what is going on?

      Please can you guys help? advice anything?....
       
    10. EasyRhino

      EasyRhino Well-Known Member

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      Year and Model:
      '02 Limited 4.6L 4x4
      Dude, start a new thread instead of piggy backing onto this one. Your symptoms will get folk's attention. Be sure to describe what truck/engine/tranny you have, and be patient. The traffic here is knowledgeable but not heavy.
       

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