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2002 Mercury Grand Marquis Question: P0304 Cylinder 4 misfire / head gasket issue?



msomats, Lynn, MA, October 14, 2009, 12:19

4.6L v8 with mil light on code is P0304 Cylinder 4 misfire. Coolant overflow was light brownish in color. Could this be a blown head gasket? If so , what is a ballpark estimate to have this repaired

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  • Answer #1

    October 14, 2009, 13:35

    Common Problems that Trigger the P0304:
    Worn out Spark Plugs Ignition Wires, Coil(s), Distributor Cap and Rotor (when applicable)
    Incorrect Ignition Timing
    Vacuum Leak(s)
    Low or Weak Fuel Pressure
    Improperly functioning EGR System
    Defective Mass Air Flow Sensor
    Defective Crankshaft and/or Camshaft Sensor
    Defective Throttle Position Sensor
    Mechanical Engine Problems i.e Low Compression, Leaking Head Gasket(s) or Valve Problems
    are you looking to do both gaskets or only one side?

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    Visitor, September 12, 2010, 02:07

    I Have P0307 cyl 7 misfire, runs rough no smoke coolant clean but how do I find out which of these problems it really is without being at the mercy of the repair shop to be honest.

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