[AnotherM]

Hi everyone,

I have a 2012 550i and have had a rough start every once in awhile. No cel and ran smooth until now. A couple days ago I finally threw a check engine light and the car seems to start rough everytime. Always starts, but not smoothly.

I ran the misfire counter on my scanner and cylinder one showed intermittent misfires. I then switched the coil from 1 to 2 and again watched the count. The misfires stayed on 1 so I know the coil was not the issue. I turned off the injectors one by one and watched, all consistently caused rough idle.

Fuel pressure on both rails measured 50k consistently during all of this.

So, I had planned on swapping all coils prior to this as well as plugs since I was planning to install a bunch of mods in a couple of weeks. I already had the coils so I decided I might as well install them. I replaced all coils and while doing so I replaced the spark plug on cylinder one. When I pulled the plug, it was completely fouled. I now believe the injector for cylinder 1 is the cause for all the problems.

Anyone experience this or what does everyone think? I am happy to report that in do have index11 injectors so I will be able to swap just the one.

[AnotherM]

Anyone have any advice?

[Anzafin]

Well index 12 injectors are the newest ones and recommended.

[BurrNinja]

Only thing I've heard are injectors going out a lot. If there is an update to them I'd try that specially if the spark plug is fouling out.