[Suvorovo]

Chasing down a missfire cylinder 3 issue (29CF). Missfire started to happen when car was at operating temperature and gunned it at WOT, so I suspect it's a blown/defective coil. I recently had a bunch of work done on my car to replace broken cylinder head bolts. OEM coils (130k miles) and aftermarket plugs were replaced since the coils fell apart during removal with bosch coils and bosch plugs. I understand bosch coils are subpar.

I don't have many options on coils since my car has the old style connector (offset connector centering tab). Are these delphi coils the same? FCP Euro claims the quality is the same, just the boot is different.

New style connector:

https://www.fcpeuro.com/products/bmw...-12138616153-1

Old style connector:

https://www.fcpeuro.com/products/bmw...delphi-gn10328

Didn't have time to troubleshoot the coils/plugs. At first I thought they weren't connected since several coil connectors weren't seated properly. Initially idled and revved just fine, but after I buttoned it up and drove a couple of miles, the missfire came back at 3k RPM although not as bad as before when the car was undrivable. Hopefully the mechanic didn't damage an injector or anything else in the process, although start up and idle are generally fine is code is cleared. Since the old style connector delphi coils are more expensive, I just purchased a $22 bosch one and will return the defective plug/coil. If that's not the issue, I'll go to the mechanic since it could be something else that he worked on (intake manifold was removed, fuel line disconnected).