I have an 04 ford f250 5.4liter gas and was having trouble with missfires my friend said was probably a bad coil so I checked with ford they wanted like $100 ea. So I found coils through summit racing (summit racing brand ? ) for like $250 for a set of 8. Replaced all 8 not knowing what 1was bad. About a month later bad coil again waited for check engine light to come on replaced the bad 1 great for a few weeks THEN AGAIN another bad coil ......... Anyone have any idea as to what might be making these coils go bad constantly PLEASE HELP THANX

 

These coils have been modified because they were troublesome. Your best bet is to get the latest from Ford. Why not just replace 4 with the latest ones from Ford. And then you can see what results you get for half the cost. Also a quick check of the charging system is in order(for over charging).

 

The last ones I tried were accell super coils seemed to last a bit longer but still didn't last !! I can't seem to bring myself to spend 4 times the price for a single coil

 

How do I check for overcharging ? Voltmeter on the battery while engine is running ? Around 14-16 volts ??

 

If you're getting between 14 and 16 volts, that's normal. That price you state for the coils from Ford is really high. I would try another dealership. Must agree $100 per coil is crazy. When you replaced the coils did you use the dielectric grease on the boots? Are you sure they were placed all the way down on the plugs? Did you check the plug gaps? All these little things add up and could cause problems which may not be directly related to the coils themselves.