Misfire, surprise suprise

[M5.tom]

Hi guys, another misfire post.

A bit of history, a few weeks ago I had a misfire on cylinder 8. I pulled the plugs, swapped the coils etc over (stayed on cyl 8) and a friend of mine a lot more clued up than me tested the power with a multimeter and diagnosed it as a faulty DME. I had the old one cloned and onto a used replacement and that solved the issue.

The next day I did a few hard pulls to test and it was fine, the day after (30 miles of driving) I did another hard pull and came with the same error and went into limp mode and running like a bag of shit. I plugged it in this morning and came up with misfire on cylinder 1 this time. (Attached a pic of the codes). Swapped the coils pack with cylinder 4’s coil and misfire stayed on cylinder 1. Wiring looks okay to my eye, gonna ask my mate to check with his multi metre again when he’s next around.

I know if one dme has gone the other one won’t be far behind but surely more than 30 miles?? Does anyone have any ideas???

For background the cars on 90k miles, rebuilt 10k miles ago. unsure for certain but I suspect it’s been mapped as it has sports cats but don’t know for sure… only owned it a month and done 150 miles on it 🙃