I have a 2001 Jeep Grand Cherokee Limited, V8. It started running rough and the engine light came on. Read the code, Po304. Replaced the coil pack on that cylinder. it ran fine for about 3 weeks. it started running rough again light came back on again. Read the code, Po354. Thought maybe the coil was bad again so swapped #4 and #6 coils, cleared computer and started engine again. Same results so I know it is not the coil. Did some testing and found the coil plug had constant power but no pulsing signal. Did the bad coil burn out one 'channel' of the pcm?