OK guys, need some help if we're going to get to Grandma's house this Christmas.

Out of the blue, single cylinder misfire early '02 Libby limited 3.7L V6 ~ 85000 Miles (149KM eh). It's got a year old set of iridium plugs, other than that the 'tune up' is stock. Starting to snow like mad, so pulling the plugs right now isn't going to happen. I'm suspicious of the coil packs (this happened once previously, about a year ago - I messed around with the plugs and it went away - hence newer set of iridium plugs), is there a test procedure for them (have Fluke DMM) or does someone know the pinout?

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2002 Libby Limited Mall Crawler with occasional fire road hustle.

Did you get a code? I had the same thing a few weeks ago after changing my radiator (it was Cyl6) and I just cleared the code and it hasn't happened since. I know it sounds crazy but I frequently get glitches in mine. I've got a lot of gremlins living in my Jeep. Most are electrical. Sometimes I just unplug the battery for a bit and let them out.

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02 Limited 179K (GONE)
05 Limited 71K (DD)
Lots to do... too little time.

There was a code present, though now it's gone (I removed battery -ve to clean the post - mild corrosion). It's not a hard miss, it occasionally fires on all 6 but it's rare. I can't complain, it's been an excellent rig to date - I'll pull the plugs and do a sim/difference reading on the coil packs tomorrow.

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2002 Libby Limited Mall Crawler with occasional fire road hustle.

That sounds a lot like mine. I had it idling 10-15 minutes, warming up after my radiator swap and I shut it off for about 10 minutes. Went back to go for a test ride and it was misfiring and threw the CEL. I had some other things to do so got back an hour later and I checked it and saw Cyl 6. Cleared it and it was fine. My coil plugs are toast from the last time I pulled the "valve" covers. I threw a #2 exhaust rocker last year (that was an interesting sensation) and the plug locks for the coil packs were VERY difficult to remove. I'm always afraid they won't stay locked and start throwing a misfire.

Good luck and Merry Christmas!

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02 Limited 179K (GONE)
05 Limited 71K (DD)
Lots to do... too little time.

Thankfully an easy repair. #6 spark plug wasn't sealing properly - tension backed off probably due to hardened gob of copper anti-sieze under washer - if you want something done right, do it yourself. Cleaned the anti-sieze threads on all the plugs with brake clean, gap and reinstall plugs with a drop of engine oil on the threads and a dash of dielectric grease on the electrodes. Ticks over smooth as butter.

Thanks for your input 02blue, Merry Christmas to all!

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2002 Libby Limited Mall Crawler with occasional fire road hustle.