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n2umr 01-26-2011 09:25 AM

2007 Expy P0308 code
I started getting a misfire code, P0308, on my expedition these last few weeks. It only happens under hard acceleration when cold so I am assuming it's a weak coil. Is the number 8 cylinder in the back on the drivers side, just looking for clarification.


n2umr 01-31-2011 03:15 PM

Well, changed the coil and no change. I guess the plug is next. Maybe run some good injector cleaner also. Any suggestions?


function12 01-31-2011 03:19 PM

You are doing what I would have done. You can also just move the coil pack to see if the misfire follows it.

n2umr 02-05-2011 10:46 AM

Changed the plug today and it seems to have fixed the problem. I was really shocked as to how bad the one I took out was worn. If they are all that bad maybe I should change them all and hope I dont break any.


someday 03-13-2019 12:10 AM

same problem 2011 with 120k on plugs. number 8 plug center electrode was missing platinum tip ~0.075" gap

pdqford 03-13-2019 01:48 PM

Must be that’s why Ford recommends changing the sparkplugs at 100k miles ;-)

And most don’t realize that running with excessive spark plug gaps puts undue stress on the ignition COPs.
When the COPs generate maximum voltage and still can’t get that voltage to ground (via the sparkplugs gap), it sets up oscillations in the COP’s secondary windings which eventually melts the insulation of the windings and suddenly the COPs start failing.

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