Mechanics

MISSING ON 4 PLUGS

2003 Mercury Marquis • 136,036 miles

I have 4 codes p0354 ignition coil d primary/ secondary circuit it aslo have po356 and po355 po357there all say the same thing what could because then and what is the primary and secondary I have change the spark plugs and the ignition coils but they still not working
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Foguie mckinnie
May 4, 2013.




If you lost an entire bank, inspect the wire harness very carefully for any breaks or any creatures that ate throught the wires.

Were the old coils wet from the intake? If they were, the intake would have to be replaced.

If both are fine, the return to the pcm has to be checked for opens or bad pcm but that is the very last thing to check.

Roy



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