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P38A Help with P38 rough running 4.0 V8

Discussion in 'Range Rover' started by Sophia2007, Nov 28, 2018.

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  1. Sophia2007

    Sophia2007 Member

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    Hi all

    I need some help with my 2001 4.0 V8 LPG rough running.

    When it is cold on petrol it lacks power and pops and bangs when trying to accelerate, when it warms up a bit this problem passes.

    Then when you are cruising between 40 and 60 it misfires you can feel a juddering where it is not running smoothly, to compensate i tend to accelerate and slow so i am speeding up and slowing down constantly to avoid the juddering. This problem happens on both petrol and LPG running.

    Plugs have been changed using good Magnecore leads any ideas what is causing the problem it is getting rather annoying now.

    Thanks
     
  2. wammers

    wammers STILL BREATHING. Donater

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    Reminds me of a Tom Jones song. "It's not unusual". Get some diag on it.
     
    Mark Piercy likes this.
  3. Sophia2007

    Sophia2007 Member

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    Ok can you recommend any software i can buy online for Diagnostics?
     
  4. Datatek

    Datatek Well-Known Member

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    Blackbox Solutions Nanocom. Not cheap though.
     
  5. wammers

    wammers STILL BREATHING. Donater

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    Good OBDII set should read your engine. Won't do anything else though. You need Nanocom for the rest and for full fat engine diag.
     
  6. Grrrrrr

    Grrrrrr Well-Known Member

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    Hmmm, @Saint.V8 has experience of rough running v8s ...
     
  7. Henry_b

    Henry_b Well-Known Member

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    'Ave a look at the Coil packs

    Could also be the CPS playing up
     
    Last edited: Nov 28, 2018
  8. Mark Piercy

    Mark Piercy Well-Known Member

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    Did it have the same problems before the plugs and leads were changed?o_O
    Have you checked to see if any vacuum pipes or air pipes have become dislodged?
    Is there an engine warning light?
     
  9. calguy

    calguy Member

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    +1 on checking both coil packs. I kept having a misfire on cylinder 7. Changed the spark plugs (#7 was burnt) and wires but kept misfiring. Then I checked the spark on #7 comparing it to #1 and it was very faint. Ended up replacing both coil packs and now all is good:). Mine is a petrol not LPG though.
     
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