Replaced MAF, after the engine died on the drive home.
SES light did not appear.
Ran the scan code on it right after it died. got the following (pending) codes
P0011 - (shit) bank A timing over advance
P0102 - low MAF reading
Left it for 20 mins on side of road and re started & re scanned.
P0102 - low MAF (pending)
Drove home gently. Ordered and replaced MAF. Cleared codes. P0102 has cleared and hasn't come back. Car is much smoother to drive. Didn't realise it was running rough.
TL

R - should I be worried about a once off pending P0011 code?
Our X5 has 225k km on the clock.