hillja

on my '04 150 with a 5.4 v-8 the above DTC keeps reappearing after swapping out the coil on #6 cylinder 3 times. I have also replaced the wire connector on top of the coil and have soldered the wires together, so I know that there is a good connection. Symptoms just prior to it 'throwing" the code include...smooth running at highway speeds, then she shudders and stumbles for about 5-6 seconds before returning to smooth running with the "light" on. Any ideas ?????
All plugs and coils have been replaced within the last few thousand miles...

redfishtd

P0356 is stored when the PCM detects an open or short with the driver coil dedicated to coil #6. In some vehicles, the PCM will actually go ahead and shut down this coil’s fuel injector to prevent further damage.
Put a volt meter on 12volt side of coil.
You realize that 12 volts is standing on all the coils one side, Make sure its there . . The pcm pulses the ground side . If that point is shorted to ground ,meaning your harness in trouble you will get this symptom .
I hope you have changed out the plug and boot as an overload can damage this circuit . There have been reports of a short in wiring harness near number 6 ,rubbing on a bracket .
Use contact cleaner on harness plug . If its not locking on replace it and solder connections .