Hello, I'm Brad. I just joined your forums.
I recently bought a 1998 Grand Marquis with the 4.6L. It had sat for a couple months without being ran but when I bought the car a few days ago it ran perfectly. Yesterday I was pulling into the parking spot in front of my house and when I shifted from drive to reverse the car stalled. I put it in park and restarted the car and it was running very rough and the CEL was lit up. I managed to get it off the road and I started doing some diagnostics. I replaced all of the plugs(there was no coolant in the spark plug wells) just as good measure but this didn't help the situation at all. With the engine running I pulled off each coil-pack connector individually and on cylinders 4-8, unplugging the coil made the engine run even rougher. On cylinders 1-3, unplugging the coil had no effect on the engine. I pulled each coil individually and inserted a spark plug in the end of the boot and none of the 3 coils were firing. I broke out my noid lights and my volt meter and I seem to have found the problem. All three coils are getting 12V to the positive side of the coil connector but there is no ground pulse when cranking/running on the other side of the connector. I've tried the noid light in cylinders 4-8 and it flashes under cranking for those 5 cylinders but there is no flash on 1-3. Any ideas guys?
Thanks in advance,
Brad
I recently bought a 1998 Grand Marquis with the 4.6L. It had sat for a couple months without being ran but when I bought the car a few days ago it ran perfectly. Yesterday I was pulling into the parking spot in front of my house and when I shifted from drive to reverse the car stalled. I put it in park and restarted the car and it was running very rough and the CEL was lit up. I managed to get it off the road and I started doing some diagnostics. I replaced all of the plugs(there was no coolant in the spark plug wells) just as good measure but this didn't help the situation at all. With the engine running I pulled off each coil-pack connector individually and on cylinders 4-8, unplugging the coil made the engine run even rougher. On cylinders 1-3, unplugging the coil had no effect on the engine. I pulled each coil individually and inserted a spark plug in the end of the boot and none of the 3 coils were firing. I broke out my noid lights and my volt meter and I seem to have found the problem. All three coils are getting 12V to the positive side of the coil connector but there is no ground pulse when cranking/running on the other side of the connector. I've tried the noid light in cylinders 4-8 and it flashes under cranking for those 5 cylinders but there is no flash on 1-3. Any ideas guys?
Thanks in advance,
Brad
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