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  1. #1

    Default 94 K1500, 250,000 miles 5.7 Truck auto trans stalls at idle

    9.8 miles into a 10 mile commute, the truck starts stalling - almost like running out of gas. Over the next couple of minutes, it got progressively worse - any time I put it in gear it instantly stalled. I limped to a parking spot and towed it home.

    The truck has for the last year or so thrown a 32 (egr valve) code - the diaphragm is known bad, but the truck ran fine. After towing it home, it also threw a 13 Ox sensor code.

    I have;
    - replaced cap, rotor and wires
    - checked compression. >120psi in all cylinders
    - replaced the throttle position sensor
    - tested the ignition module (good)
    - replaced the fuel filter
    - replaced the timing chain (the old one was very slack but not skipped)
    - replaced the o2 sensor
    - adjusted the timing both directions while running.
    - plugged the EGR vacuum solenoid to eliminate that small vacuum leak.
    - checked for side play in the distributor - the rotor only moves a very small amount (.005"?)

    At this point, it starts and runs if you pump the gas and keep the rpm over 2500, but is completely undrivable. I'm at a loss regarding next steps. Can anyone help?

  2. #2


    Sounds like you've got a plugged cat.

  3. #3


    Check your fuel pressure.
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  4. #4


    Thanks for the advice guys. I unbolted the y-pipe at the headers. Same behavior but louder, so it's not the catalytic converter.

    I'm going to borrow a fuel pressure gauge tomorrow. The truck will run at high rpm if you work the throttle... but it won't idle, so low fuel pressure seems counter intuitive - it runs worst when it needs the least fuel.

  5. #5
    Sr. Engineer
    Join Date
    Dec 2011
    11-22-boogie woogie avenue


    Does it back fire any through the throttle body? Sounds like iacv, or the pickup coil.
    Pickup is mounted to the dist. shaft . Can ohm it out with a meter.
    Disconnect yellow and green wire from the ignition module .
    Set meter to low ohm,s setting probe the wires should get 700 to 1200 ohm,s of resistance.
    Also try the coolant temp sensor located at the thermostat housing cost 11 bucks get it out of the equation.

  6. #6


    Yes, it occasionally backfires, but adjusting the timing by ear has mitigated most of it.

    I've been suspicious of the distributor. Thanks for the pickup coil tip. Is there a way to diagnose the IACV?

  7. #7
    Sr. Engineer
    Join Date
    Dec 2011
    11-22-boogie woogie avenue



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