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As I posted earlier, I finally got the cooling system on SWMBO's Z4 all sorted out (pretty much replaced the entire cooling system, except the radiator). Things have been going smoothly for a couple of weeks, but then the car started misfiring, most noticeably when stopped and when just starting out. It seemed to smooth out a little at speed but still not as smooth as I know it should have been.
I put the code reader on and got a code for a misfire in #3. My first step was something I was going to do anyway, and that was to replace the spark plugs with NKG Laser Platinum. I wasn't really expecting this to fix the issue, but I had this planned anyway. As expected, it was still missing on #3 after plug replacement.
My next step was to swap the ignition coils for #3 and #4 cylinders. I then reset the codes and took it for a drive. I checked the codes again and the misfire code move to #4.
Using my remarkable powers of logic and deduction, I deduced that the culprit was a bad ignition coil pack for the misfiring cylinder. I swapped the coils back and replaced #3 with a new coil and viola - it's fixed! Her car is now running as smooth as ever.
I put the code reader on and got a code for a misfire in #3. My first step was something I was going to do anyway, and that was to replace the spark plugs with NKG Laser Platinum. I wasn't really expecting this to fix the issue, but I had this planned anyway. As expected, it was still missing on #3 after plug replacement.
My next step was to swap the ignition coils for #3 and #4 cylinders. I then reset the codes and took it for a drive. I checked the codes again and the misfire code move to #4.
Using my remarkable powers of logic and deduction, I deduced that the culprit was a bad ignition coil pack for the misfiring cylinder. I swapped the coils back and replaced #3 with a new coil and viola - it's fixed! Her car is now running as smooth as ever.