Geargambler
Well-Known Member
I'm about to embark on yet another troubleshooting episode for the cylinder 6 misfire. I have a 2017 Expedition limited. First time this happened was back in November 2023. I bought an NGK coil and amazon delivered it next day. I swapped the coil and it ran perfectly... for 5 months. Then the code popped up again with the same symptoms, CEL, running rough, missing, limp mode. I bought another NGK, removed the 'old' NGK and again it ran perectly. So good that I took my family while pulling an enclosed car trailer with my cobra in it to carlisle ford nationals and back. No issues at all. I went as far as buying a set of 6 coils from a vendor on ebay that are OEM replacement motorcraft. I did a remove and replace with the motorcraft and immediately it threw a code and ran like crap. I put the NGK back in and it was fine. I returned the motorcraft set. Twenty days later, the misfire is back again. Same cylinder 6.
First thing I'm going to do is pull the coil and plug to see if the plug is fouled. If not, I'm going to swap the coil from 6 to 4 and see if 4 misfires. When I do this I'm gong to pull the negative battery lead to reset. I have a code puller, but I want the ECU to re-learn.
Possible causes from reading and searching: bad coil, again. injector clogged. faulty or broken wire. ECU issue.
Follow along as I find the root cause for this nonsense.
Few questions!
What aftermarket coils is everyone running? Part numbers?
I replaced the plugs not too long ago with OEM motorcraft. Read some threads about NGK plugs one heat range colder. They worth it? Part number?
First thing I'm going to do is pull the coil and plug to see if the plug is fouled. If not, I'm going to swap the coil from 6 to 4 and see if 4 misfires. When I do this I'm gong to pull the negative battery lead to reset. I have a code puller, but I want the ECU to re-learn.
Possible causes from reading and searching: bad coil, again. injector clogged. faulty or broken wire. ECU issue.
Follow along as I find the root cause for this nonsense.
Few questions!
What aftermarket coils is everyone running? Part numbers?
I replaced the plugs not too long ago with OEM motorcraft. Read some threads about NGK plugs one heat range colder. They worth it? Part number?