1993 Silverado 1500 popping/backfire

Discussion in 'General Chevy & GM Tech Questions' started by slavaka, Aug 7, 2008.

  1. slavaka

    slavaka New Member

    I just bought my truck a few days ago so im trying to work out all the bugs. When I start driving it wont backfire unless I am bogging the motor in a lower gear than I should be in or if I have high rpms and press in the clutch. Also does it on coasting with high rpms. If I shift at low rpms I can avoid most of the backfiring noise, and If I am on the highway I dont hear it either. Everything seems fine once I am going. I dont know whether to explain this as backfiring or something else, but all the sound seems to be coming from under the hood. My thought on this is possibly a bad plug or wire, but I wanted to ask before I did anything. If anymore info is needed on my truck just let me know.

    Last edited: Aug 7, 2008
  2. slavaka

    slavaka New Member

    Nobody? If im asking a stupid or obvious question dont hesitate to tell me that. Im new to trucks so im short on information.
  3. collinsperformance

    collinsperformance Epic Member 5+ Years 500 Posts

    what have you done or looked at?
    could be timing, bad fuel, dirty motor, PCV valve.
    check timing add seafoam to the tank and intake and see if that helps any. clean the PCV valve or replace it.....mike
  4. slavaka

    slavaka New Member

    Ok, replaced the pcv valve and the hose today and also put some seafoam into the tank and oil and still no changes. I have no idea how to check the timing, but wouldnt it be backfiring more often if it was the timing?
  5. voodoo 350

    voodoo 350 New Member

    chances are if you did everything mike suggested except the timing, that is probably what it is. you will need a timing light and a 9/16 distributor wrench. the light will come with instructions that are pretty cut and dried. If you have an inkling of mechanical ability you should be able to figure it out. Other than that just do the cheap stuff first, like plugs, wires, distributor cap and rotor and you may find that is where the problem lies. you should also have an HEI or coil in cap distributor and if not properly grounded it can cause arcs and missfires which lead to your specific problem.
    hope this helps and good luck!!!
  6. voodoo 350

    voodoo 350 New Member

    P.S. I also had a truck do what you described to me once and it was a bad crankshaft positioning sensor but you should have a check engine light on if that is the case.
  7. slavaka

    slavaka New Member

    I appreciate the help. Ill see what I can do when payday rolls around and hopefully ill have some luck on my side.

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