Intermittent miss - 2000 Contour V6

2000 Contour V6 2.5L Duratec engine, 60K miles on original plugs
I have recently been having a problem with intermittent miss. I took it by AutoZone and they checked the Check Engine code. The only code was
"misfire - cylinder 1."
I removed #1 plug and it was very clean, no fouling, gap very slightly over original spec (about 0.057" vs 0.054").
The engine starts and idles well, although idle rpm has always seemed a little high to me. I can drive the car 4-5 miles with no missing, then sometimes it begins, sometimes not. This makes me think it might be heat related.
The spark plugs are supposed to last 100K miles, so it's not officially time to replace them yet.
So any suggestions are welcome. Should I go ahead and replace the plugs, should I add some fuel injector cleaner?
Thanks, Craig [to reply directly, change the VERB to a NUMERAL]
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Try replacing ignition wire
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