PCM
I just changed out the ignition coils to performance ones only to find out they will not work in ecoboost engine, so I put the old ones back in (I have had problems the last little while with back fire and misfire) they were going into garbage so I did not mark them. I put the old coils back in reset the pcm for aboput 20 mins and now truck will not start.
Would this be due to bad coils by any chance? Any ideas?