4.2 Random misfire and no power

GordyGordy Member Posts: 4
edited December 2018 in GMC
I have a 2004 envoy with the 4.2 I replaced the plugs and coil packs 6 months ago and it has run perfect. I went to start it up las week and it ran like crap. I put my code reader on it and got codes for the cam position sensor and the vvt actuator solenoid. I replaced both. Now I onlt get the p0300 code and it runs horrible. Any ideas? Anyone? This has been a great vehicle and I can't afford to replace it.


  • Jompa2210Jompa2210 Member Posts: 1
    If you have a code or dash reads reduce power change the gas pedal which has a built-in governor and connects electrically to throttle all you have to do it's change the gas pedal again if your dash reads reduced power [email protected]
  • GordyGordy Member Posts: 4
    Thanks. I will try that and let you know how it works.
  • thecardoc3thecardoc3 Member Posts: 5,727
    A P0300 is a random misfire code and would not be caused by a problem with the pedal position sensor assembly. First thing you need to do right now is go to live data and see which cylinder(s) is(are) being identified as misfiring. Then check to see where the camshaft timing desired and actual are and if the cam is in time. Check to see how much of a command (duty cycle) it is taking for the computer to try and control the timing.

    From there regular engine condition testing should be performed such as compression and cylinder leakage. But don't start throwing parts until you actually prove that something needs to be replaced.
  • GordyGordy Member Posts: 4
    Thank you.
  • rickdonrickdon Member Posts: 123
    Check also the cam position sensor if it is dirty.
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