Good morning, i have not used this site before so thank you in advance for taking the time to read my questions and respond,
I have a 2016 f 250 6.2 gas that has thrown a P0351 code. it has 91,000 miles so i know im due to have new plugs but that does not seam to be the issue. Im not getting any power sent to coil 1. i swapped with coil 3 and still no spark on coil 1. so its not a coil issue, i put two new plugs in it so not a plug issue, tested voltage and i am getting 12 volts at the coil plug but when i test the rest of the plugs on that side they read below 12 volts. resistance at the plug shows nothing when i tap the block, if i test it against the truck frame it will go wild, that is confusing to me.but Ive been using a hand held multimeter and i could not be getting good contact.

So do i have an open ground in the wire harness or is the pcm bad? maybe something else?

Another interesting thing is that when the engine is running i can unplug the rubber lead from the top of the coil that sends charge to the bottom spark plug and it will arc on every coil expect #1 even after i swapped the 1 and 3 coils... and swapped the leads.

Any diagnostic help would be appreciated. Thank you

 

Well, I guess what I would do myself, because it sounds like you have fire, you're just not completing the circuit. On #1 coil, find the ground wire, then tap into it and run a temp ground wire to the frame or some other good area then see if #1 starts working correctly, If it does then you'll have to chase that ground wire back through the harness until you find the problem. It could be the PCM / ECM but you'll have to trace the circuit all the way back anyway. Another thing to try is to pull the main plug on the ECM and make sure there are no bent or broken / corroded pins. or make sure none of the pins are loose and pushed back in the plug causing a bad connection.