2000 4.0 classic magor misfire cycl.4
#3
Old fart with a wrench
Pull the plugs and do a compression test. Look at the plug from #4. Look at the plug from #3 because they fire together at the same time. It might be possible there's a bad connection on the #2 coil ground causing a low voltage spark. The plug connector where it connects to the harness has 4 pins. One is power and the other 3 are ground connections to the PCM. It's unusual but sometimes the sockets can push out the back of the connector and not make a good contact with the pins. If you hadn't already changed the coil pack, I would have suggested it was shorted internally.
The coil pack system uses 3 coils to fire 2 plugs at the same time, one on compression and one on exhaust. Power is constantly applied to the 3 coils and are grounded thru the PCM drivers. The PCM UNgrounds one to make it fire. #1 and #6 fire together, #5 and #2, #3 and #4.
The coil pack system uses 3 coils to fire 2 plugs at the same time, one on compression and one on exhaust. Power is constantly applied to the 3 coils and are grounded thru the PCM drivers. The PCM UNgrounds one to make it fire. #1 and #6 fire together, #5 and #2, #3 and #4.
Last edited by dave1123; 09-20-2018 at 05:02 AM.
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