HELP! - I have a 1997 F-150, 153,000 miles -yesterday the cel went on flashing, engine lost power - barely got home. Checked the code, PO308, misfire in #8 cylinder. Changed out the plug, it looked bad. Changed the coil wire as well - erased code, drove it a bit - same thing.
Checked the forums here, followed some similar issues; changed the fuel filter - replaced the fuel injector - erased code, and alas - same issue! PO308 pops up.
So, I remove a sparkplug from #1, changed it with #8, erase the code, and still - PO308 comes up.
Truck seems to run a lot better though, although that cel flashes again and the same code comes up.
What have I missed? - about four months ago I replaced a bad O2 sensor, not sure if that has any connection - last thing it could be is the distributor itself? maybe?...any suggestions? A thousand thanks!!!

 

Do you have the 4.6l or 5.4l?

 

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4.6...starts up fine, runs a little rough - pretty sure a plug isn't firing...