Edmunds Answers



  • MrShift@Edmunds 02/14/12 11:18 am PST

    What a mess....sounds like basic incompetence to me...and I have no idea what that blog is talking about---doesn't make sense. The only "ring" i know of that relates to engine miss would be the crankshaft positioning sensor. Nor does it make sense to replace a timing chain to fix an engine miss.

    I'd just get the truck out of there and find someone who can diagnose the problem properly. Sounds like everyone is just guessing, using your checkbook.

    Here's a basic run-down of your ignition system:


    The electronic ignition system is a coil-on-plug system. The coil-on-plug ignition system consists of the following components:

    The CKP sensor:

    • is a variable reluctance sensor.
    • is triggered by a 36-minus-1 sensor ring mounted on the crankshaft.
    • provides base timing and crankshaft speed (rpm) to the powertrain control module (PCM).

    The eight separate ignition coils:

    • change low voltage signals from the PCM to high voltage pulses.
    • produce the high voltage pulses to the spark plugs.
    • are connected directly to each spark plug.

    The spark plugs:

    • change high voltage pulses into a spark which ignites the fuel and air mixture.
    • originally equipped on the vehicle have a platinum-enhanced active electrode for long life.

  • Stever@Edmunds 02/14/12 12:33 pm PST

    You can reply in this thread by clicking the Answer this Question button and that will help keep all the information in one spot. Thanks!

  • MrShift@Edmunds 02/14/12 12:43 pm PST

    Well I'm not in the middle of all you guys to judge exactly what's going on, but if the timing chain idler was broken, your truck would either a) not run at all or b) be making a horrible racket.

    But let's say all that was necessary.

    Sure a computer could cause this but I doubt it. Computers rarely....RARELY...go bad....if anything, there could be problems in the wiring harness.

    As for the variable valve timing issue, I could see that causing a loss of engine power, but not a total misfire in two cylinders.

    If they think two cylinders are not firing, then they have to check the coils for those cylinders, and the injectors, and work from there.


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