Chevy backfire and bucking

Discussion in 'Feedback, Help and Suggestions' started by steve porch, Apr 2, 2018.

  1. steve porch

    steve porch Newbie

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    I have a 96 Chevy with 305 5.0l. has about 153k. I recently did plugs, wires, distributor cap and rotor. I have a new fuel tank fuel pump and sending unit. On highway and mid ranger rpm speed my truck backfires and bucks between 1-2 rpm or if my foot is slightly on gas. The bucking is like the engine stumbling you can feel it jumping basically. I can run 87 or 93 gas and doesn't make a difference. I don't know what to look at next? Fuel injector cleaner doesn't help much either
     
  2. evilunclegrimace

    evilunclegrimace Does not always play well with others

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    How about you go back and make sure that you don't have a loose wire or have 2 wires crossed on the cap.
     
  3. steve porch

    steve porch Newbie

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    So the wires are all tight and are going to the correct places. The truck will idle very nice and runs smooth past 2 rpm. the problem is between 1-2 rpm and at a low constant speed when under load
     
  4. grampadirt

    grampadirt On MEDICARE Officially Old

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    Could be the ignition control module in the distributor(under the rotor).
     
  5. evilunclegrimace

    evilunclegrimace Does not always play well with others

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    Check for a cracked plug.
     
  6. Oldblue98

    Oldblue98 Supporting Member

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    Is this what it was doing before the tune up ? Or did it start after you did all this ?
     
  7. Tom Nassar

    Tom Nassar Newbie

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    I'm having a similar issue and I'm suspecting the EGR, but not sure yet.
     
  8. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    I agree, either ICM or your base timing is off (or you have a big cam?). Anyway, it sounds like you're either too far advanced or your AE (Acceleration Enrichment) table needs adjusting. AE acts like an accelerator pump in a carb - it gives you an extra squirt of fuel when you hit the gas.
     
    Last edited: Jan 24, 2019

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