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P38 is really stressing me out

Discussion in 'Range Rover' started by grafter, Jun 12, 2018.

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  1. grafter

    grafter Member

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    Hi all I have 2000plate 4.6 v8 petrol / LPG omvl multipoint 147000miles
    I’ve had an on going problem for a long while my problem is the p38 is trying to stall when approaching traffic lights and holding back on dual carriageway journeys
    This year I’ve replaced
    Maf sensor with Bosch
    Iacv
    Had adaptive values reset
    Replaced lpg injectors
    Replaced all gaskets and rubbers in lpg condenser/vapouriser
    Changed gearbox oil and filter
    She was running brilliant for a few months and after lpg over haul she ran perfect so much power and better fuel consumption but then started to nearly stall and hold back after a few weeks so new maf and had adaptive values reset and run lovely again for about a week now running worse than ever
    It’s not bringing up no codes either
    Last year I changed exhaust gaskets
    Inlet manifold gasket
    Spark plugs
    Water pump
    Radiator
    Thermostat
    Crank position sensor
    Throttle position sensor
    Can anyone help and advise what to do next or know what’s wrong with it
    Any help much appreciated
     
  2. wammers

    wammers STILL BREATHING. Donater

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    Fit diesel engine.
     
    sheriff, Saint.V8 and Jake Hewitt like this.
  3. Saint.V8

    Saint.V8 Dyed-in-the-wool 100% RR Junkie

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    Coked up O2 sensors?

    Worn mechanical components? I.e Camshaft or followers?
     
  4. Grrrrrr

    Grrrrrr Well-Known Member

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    Why does it get better each time he changes the MAF? Might be worth cleaning the MAF and see if it improves?
     
  5. Saint.V8

    Saint.V8 Dyed-in-the-wool 100% RR Junkie

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    I suggested O2 sensors, as they work in conjunction with the MAF.....he has changed everything else!!!

    If it was an aftermarket MAF then I would say try an OEM one and see if that helps - AM MAFs have been known to fall over after 6 months or less!
     
  6. Datatek

    Datatek Well-Known Member

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    +1
     
  7. Grrrrrr

    Grrrrrr Well-Known Member

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    Says Bosch for the first one so presumably the replacement too. O2 sensors makes sense.
     
  8. grafter

    grafter Member

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    Thanks for the reply’s I cleaned both oxygen sensors and she ran perfect again I’ll just see how long it lasts this time or should I just renew both sensors
     
  9. ukadamwest

    ukadamwest Well-Known Member

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    how long have the cats been on ? if they are old and breaking up / clogged that would cause the symptoms. get a rubber hammer or the side of your fist on your back and tap or thump the cats.. do they rattle at all ?
     
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  10. tomcat59alan

    tomcat59alan Well-Known Member

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    They will after a good thumping.;):D
     
  11. Grrrrrr

    Grrrrrr Well-Known Member

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    That's the question: why does stuff keep clogging up?!
     
  12. ukadamwest

    ukadamwest Well-Known Member

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    you asking about your exhaust or the P38?
     
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  13. Rick-the-Pick

    Rick-the-Pick Active Member

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    Heres a long shot. On the front of the engine, you have two throttle cables with a thumb wheel. These can be knocked & this can cause high or low revs. A slight adjustment may be all that's needed. A garage changed an alternator on a V8 & this same problem had occurred since. Umpteen visits back to the garage couldn't find the problem. We noticed the bolts were loose & this effected the tickover.
    Just a thought.
     
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