Fault codes can be intermittent. It would be easier to find if the condition were all the time. It may take 2 occurrences of P0306 to mature into an 'active' fault code & turn on the 'ck eng' light. Before that, or as a 'one-trip' failure, it may show up as a 'pending' code.
The PCM is pretty accurate about misfire faults & I'm pretty confident that it is real. The PCM can detect misfires that we can't by measuring slight changes in crankshaft speed. The crankshaft is constantly slowing down on a compression stroke & speeding up on a power stroke. It looks for that. We even out the inertia & momentum pulses with a flywheel, but they are still there.
Spark plugs can tell a story. The tip of the #6 spark plug may look different than the other five. A whiter porcelain tip may indicate a 'lean' condition. Any carbon or soot may indicate a 'rich' condition for that cylinder. Due to how intermittent this is, you may see nothing out of the ordinary.
If the XTool D7 can read stored 'freeze frame' data, copy down what the PCM sees when the misfire occurs. Is it a miss at idle or at speed? Is it during acceleration or at a cruise? Warm or cold? etc.
What conditions are present when the misfire occurs may help us to find it. See what the freeze frames have in common.
Has the top of the motor ever been apart? It is important to secure the coil/injector wiring harness so it won't wear through & short when reassembling.
Swapping the #6 plug & coil with an adjacent cylinder is a good idea. See if the fault follows the plug/coil. Look for any faint arc streaks on the porcelain body.
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The PCM is pretty accurate about misfire faults & I'm pretty confident that it is real. The PCM can detect misfires that we can't by measuring slight changes in crankshaft speed. The crankshaft is constantly slowing down on a compression stroke & speeding up on a power stroke. It looks for that. We even out the inertia & momentum pulses with a flywheel, but they are still there.
Spark plugs can tell a story. The tip of the #6 spark plug may look different than the other five. A whiter porcelain tip may indicate a 'lean' condition. Any carbon or soot may indicate a 'rich' condition for that cylinder. Due to how intermittent this is, you may see nothing out of the ordinary.
If the XTool D7 can read stored 'freeze frame' data, copy down what the PCM sees when the misfire occurs. Is it a miss at idle or at speed? Is it during acceleration or at a cruise? Warm or cold? etc.
What conditions are present when the misfire occurs may help us to find it. See what the freeze frames have in common.
Has the top of the motor ever been apart? It is important to secure the coil/injector wiring harness so it won't wear through & short when reassembling.
Swapping the #6 plug & coil with an adjacent cylinder is a good idea. See if the fault follows the plug/coil. Look for any faint arc streaks on the porcelain body.
