[Teaspoonlizard]

Looking for some help with my 116i F21.

I have had the car remapped now for maybe 3 years and have had multiple issues with misfiring. First time it happened, coil pack seemed to resolve the issue. The next, ECU repair. The next I send the ecu back for repair again, no issue so coil pack + spark plugs fixed it. The next, just a spark plug.

It's been about a year since the last problem and it's come back again, I tried replacing all plugs which hasn't resolved it. Now misfiring under load on cylinder 1. Should I try coils again?

Something that I noted when changing the spark plugs is they were ALL fouled. Looked like Carbon to me. The car was remapped at Superchips and I've asked them for their opinion on if the fuel mixture for the map is too rich but they assured me it's a closed loop system so that can't be the case.

A while back I thought it may be a leaky injector on cylinder three, but now all the spark plugs are black could all of the injectors be leaky?? Surely not, right?

Looking for some guidance here as I've run out of ideas. Can anyone offer some advice? Anyone have similar issues?

Thank you.