So my husband just replaced the spark plugs and coil packs on our 2000 Excursion 6.8L V10. Ran great for a couple days and now it's starting to misfire again. But not all the time. Last night it was pretty bad, but this morning it was fine until we drove about 20 miles then it started up again. By the time we got home it seemed to get better. Hubby seems to think it's the fuel injectors. I'm wondering if it's the electronics. The truck has 254k miles.

 

That's a good amount of miles. Hubby could be right, but before getting too involved you might suggest that he check the plug on the alternator for corrosion or looseness, poor connections there can drive the car's computer up the wall,,,,,,,,,,and sometimes the driver too !