Question about 1985 Chevrolet C1500

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Popping sound in carb when i throttle it up

I have changed the distributor and checked the timing with the advance off its in time at 4 btdc no vaccum leaks at all did the wd-40 test fuel pressure is low but just put a new pump on it even with the electric pump on it puttin out 7 psi it still pops gas back up the carb on the one side not both ??????????????

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  • Mark Paxton
    Mark Paxton Dec 30, 2008

    i have been told that i may have one lobe gone south but keep in mind that my truck has less than 100,000 miles on it  96 and change to be exact im still at a loss i how ever do have the vaccum advance hooked up to constant vaccum will that have any effect on it 

  • Mark Paxton
    Mark Paxton Dec 30, 2008

    im going to check it out is there any way other than pulling the valve coverof and taking a oil bath i already pulled the plug wires and no change with it running any other advice im open ???????

  • Mark Paxton
    Mark Paxton Dec 30, 2008

    yes i think it is number 5 cylinder but thats just a guess i have had an exhaust leak on the right side for some time i did fix it but the connection for the pipe and manifold is loose again

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  • 1,450 Answers

Sounds like you may have a cam lobe gone flat

Posted on Dec 30, 2008

  • 2 more comments 
  • TripleTauto
    TripleTauto Dec 30, 2008

    MILEAGE may not have anything to do with it i have seen them go with less mileage. the timing advance should not cause this although it should be hooked up to ported vacuum

  • TripleTauto
    TripleTauto Dec 30, 2008

    DO YOU HAVE IT NARROWED DOWN TO WHICH CYLINDER?

  • TripleTauto
    TripleTauto Dec 31, 2008

    if you have a way of measuring the lift you can rotate engine manually and see if valves are opening it is probably going to be an exhaust valve not opening

  • TripleTauto
    TripleTauto Dec 31, 2008

    if you have a way of measuring the lift you can rotate engine manually and see if valves are opening it is probably going to be an exhaust valve not opening

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something wrong here
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