cgouldy

OK I have had simular issue. One certain Coil I keep getting Code p0351 which says that the Primary and Secondary Ignition Coil Failure. I have replaced the same coild 4 times. The last time I purchased a Motocraft coil instead of aftermarket. It still would miss. I noticed that when the truck would start to miss it shut down the Fuel injector. I asked a ford machanic and several others I know say that this is normal. That when computer detects a missfire then it shuts down the coil. My problem is that I can start the car and drive 10 to 15 miles and have no miss then it will just all sudden start missing. I had truck checked at a dealer they ran there mode 6 diagnostic and said it was coil. SO I replaced coil again witht the motocraft coil cause they said it was the aftermarket coil I had on there. It still did it. When they put a noid light in it it showed that the computer was fireing the coil and said that it was not my PCM. Cause that what I was thinking it might be. Was told if computer was bad would have more problems then that. Pluss machanic friend said that the code I was getting illiminated it being the injectors, the PCM. I changed out the Cam Shaft Sensor and crank Shaft sensor today going to see if that corrected it. Was told by another machanic friend that might be my problem if they were not working properly. Will update you if that worked for me.

TRD-Toy

Uncle ford, I think you still have a coil problem and not an injector problem. 1st you are setting a coil fault code not an injector fault code. Fuel codes are 200's and ignition are 300 codes. The PCM is smart enough to shut down the injector if it has a problem with a coil, not a misfire code. Misfire is more generic code than a coil fault. Misfire, the PCM doesn't know so it just gives it more fuel because the o2 will show lean. This seems deceiving to have a coil problem
When you have switched out the coil with a known good coil! When running the coil connector will light a test light! When running the injector coil will light a test light for roughly 15 seconds! What I think is happening is; there is high resistance it the ground wire from the PCM to the #7 coil (this will light a test light but will not be sufficient to do work; or there are coil ground wires touching the #7 coil ground wire causing the coil to fire but at the wrong time. To check these two things you would need to use an ohm meter, disconnect the PCM( behind the battery box at firewall), ohm the coil ground wires leaving one lead on #7 and then check other lead to all other cylinder coil ground wire. You can check the coils ability to do work by turning #7 coil upright and put any old spark plug in it and use a test wire from threads to ground, plug should fire. I have seen wiring problems on the backside of the engine there and connectors by the starter solenoid, mice like it there and back by the PCM. Sorry this was so long but I think putting a PCM in won't fix this! JMO, I think it's a coil issue because it's a P0357 not a P02--, injector fault code. The PCM is just protecting the cat by shutting down the injector! Good luck and report back, interesting problem!!!

Uncleford

Okay guys, thanks..I will do some more checking. I didn't think about the crank/cam shaft sensors..let me know how that works for you.

TRD-Toy - if I am understanding you correctly, take out number 7 coil pack and stick another plug in the coil pack and see if it's firing? Is that right? Sounds easy enough to do!

As far as the wiring harness goes I drive this gas eater to much for anything to nest inside the engine compartment! Lol FWIW, I have checked the harness visually to look for obvious breaks and tears but didn't find any.

Thanks again for all the help!