I got code PO 305 on a 2002 Mercury Grand Marquis, what is the spark plug wire part called, is it #5 coil, and should I replace the coil and spark plug and what should the spark plug be gapped at? Thank You

I got code PO 305 on a 2002 Mercury Grand Marquis, what is the spark plug wire part called
This will have a direct coil over ignition with a coil over each spark plug. The coil is the electrical part over the spark plug. The coil also has a rubber part that is called the boot or spark plug boot. The boots can be purchased separately but the coils will come with new boots.

is it #5 coil,

Have you checked to see if there is any spark coming out of the number 5 coil?



and should I replace the coil and spark plug and what should the spark plug be gapped at?

When was the last time the spark plugs where changed? It may be due for all the spark plugs to be changed. The spark plug gap is usually listed on the emissions sticker under the hood. It should be .050 - .056 or very close to that.

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