Question about Buick LeSabre

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Miss under a load (up hill) when car is at operating temperture.worse when tranny shifts in to passing gear.Runs great cold and at slow speeds. I have replaced plug wires and plugs with some improvement but still does it. Also replaced egr valve,air filter,fuel filter,tranny filter and oil.replaced the coils and control module. Car has 70000 miles on it.

Posted by etbreezie on

  • etbreezie Aug 12, 2008

    I think I have a vacuum problem,perhaps manifold gaskets or a crack in the plastic manifold. When I step on the gas pedal the car is very reponsive even uphill.




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Explain problem in detail thanks.

Posted on Aug 12, 2008

  • Ginko
    Ginko Aug 12, 2008

    First you should have car compression checked , you can get this kind of problem when head gasket is starting to go. Check if coolant liquid level is gone down.
    Check also if one of the spark plugs is burnt or dirtier then the others car may be misfiring on one cylinder. Start replacing spark plugs, if you keep getting the problem you have a distribution problem.
    Have car computer scanned with a code reader to locate the problem.

  • Ginko
    Ginko Aug 12, 2008

    Exhaust tailpipe black on the inside is normal, check if you get white
    smoke from exhaust when engine is hot that means head gasket problem.
    If car fail going up an hill it is often a compression problem.

    If car has automatic transmission, it can be also tranny not shifting
    down gear, this usually is a module problem, but you told me you
    checked this already.

    Also a faulty throttle position sensor can give transmission problems,
    but when this is faulty you get troubles with gears on all kind of situation.



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