Hi everyone and thank you for taking the time to help me out. After many tests and letting the Ford dealer replace my pcm with a new pcm, coil pack #3 kees melting.
History:
driving one day and get a sudden misfire on cylinder #3. Get home and replace the coil pack and plug with motorcraft parts. That coi pack lasts about a week and then suddenly a misfire on #3, I pull it out and it is melted!
I think it’s a bad coil so I exchange it. 10minutes later the pack melts.
do some research and test the wires with an ohm meter and no unusual readings so I unplug the coil pack and drive it on 5 cylinders.
I decide to buy a used pcm and have the dealer install and program it which they did without diagnoses per my direction (trying to save money) and within 10 minutes after driving home the #3 coil pack is melted again!
take it back to the dealer and pay the tech to diagnose it. He says the used pcm is bad just like my original pcm. I agree to have a new pcm put in with a new coil pack and spark plug. I Pick up the truck it drives fine for a week and then out of no where #3 melts again!

I’m thinking and intermittent short in the wiring harness somewhere? Please help if you can!

has anyone seen this before?

thank you

 

Geeze I’m no mechanic just sorry you’re running into this prob . Thursday I have all plugs and coils replaced with genuine motor craft . I’m having #1 misfire for 2nd time and now #5. Very nice 2012 3.5 I picked up last month. They didn’t use motor craft when the small dealership I bought from had replaced them. I told them motocraft all the way around they said no. Heck they don’t even have a decent code reader! So I got it scheduled Thursday with a different shop. All motor craft . Do we shall see, I drove 100 miles RT today to couer d Alene. No issues. 645. 00 smacks for this repair. I sure hope this will solve the problem. Shop said no codes showing on the cam ie timing chain. Cross my fingers I’m low income. Hope you can get your truck working like it should.

 

Finally after going through all of the events above the problem is finally repaired. It was not the PCM and it turned out to be an intermittent short on the connector or wire from the PCM to the #3 Cylinder. The mechanic ran new wires from the PCM with an overlay harness to the coil pack which also got a new connector and problem solved.

I do want to clarify that the existing wiring never showed a short when using an OHM meter and honestly neither did the PCM but I guess the Mechanic felt like it was the best option at the time. Even though it was not the problem I am happy with the service at the FORD dealer, they did the wiring repair and replaced the coil pack and kept it for a few days to test drive and make sure the problem was fixed at no charge. These problems can be difficult to diagnose and in this case was never really diagnosed and so we had to throw parts at it until it was fixed.