[Bimmerson123]

Hello guys,

So, my 2010 550i gt was misfiring on bank2(all cylinders)
And it threw me some codes and DTM for misfiring and rich mixture codes.
Did a smoke test and turbo diverter valve(=wastegate actuator/electric valve)
was leaking, so I changed it. After the replacement, only the cylinders 6 and 8 were misfiring, so I decided to swap the spark plugs and coils to see if they are the issue.

While taking out the plugs and coils, I realized the coils were broken, so I replaced the plugs and coils on the 6 and 8.

After the replacement, dtm was gone and the codes weren't showing up for a couple weeks.

However, I felt like the car was slowly going back to the condition that I had before the replacement and it started throwing DTM and codes for rich mixture and misfiring on cylinder 8 only.

I haven't taken out the plug and coil to see yet, but I have a strong feeling that they have gone bad again.

My question is, what could cause the spark plug and coil pack to go bad so quickly. (It's only been 2 weeks and the issue I'm experiencing is identical as before, but less severe)

Could anyone share his or her insights on this please )