Hard cold start, bad misfire, newer plugs n wires...

Discussion in 'Chevy C/K Truck Forum' started by jval1280, Dec 9, 2013.

  1. jval1280

    jval1280 New Member

    Ok eveybody.
    Let me lay it out for you first. 97 Chevy c1500 work truck. 4.3L Vortec v-6 csfi (central sequential fuel injection). Replaced plugs n wires last year. Also new fuel pump. Ran fine for a long time. Started having starting issues which I traced back to the fuel pressure regulator. Recently replaced that, cleaned carbon from injectors, and got what I could out of the upper intake. Now I'm still having a hard cold start issue. Pulled plugs last night and cleaned them and now she's missing like she's only running on three cylinders. Raw fuel smell at exhaust. Planning on going for new cap n rotor because I know they are original. Any other ideas to point me in a different direction other than ignition system? Or has anyone else experienced this? Any help is appreciated. Also keep up the good work on here.
  2. 66 chevyman

    66 chevyman Member 1 Year 100 Posts

    Might be timing as well....does sound like a spark issue....you sure you hooked all the wires back on right? Could be a fuel issue as well.
  3. K3500 Guy

    K3500 Guy New Member

    Definitely check cap n rotor, also crankshaft position sensor? Just had to replace mine because it ran like crap. Also check the mass airflow sensor. There should be three little sensors in there. Buy some mass airflow sensor cleaner from the auto parts store. Spray it on a Q-tip and very gently clean the sensors. The only other thing I could think is maybe the egr valve could be bad. You can test that to see if it is bad or not. I would also maybe take it to the auto parts store and borrow a code reader to see if that can help you narrow it down.
  4. fugitive

    fugitive Member

    Do your best to diagnose each component suggested above with a multi meter tests are available on youtube . Whatever you do don't start throwing parts at this thing without troubleshooting 1st. I have been chasing a random cylinder misfire on my 98 for almost a month!

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