[DL7]

I had similar check engine light and codes for bad gas, airmass, rich. After lengthy diagnosis a MAF sensor was replaced and the check engine light went away. Not even a month later and less than 500 miles, I had loss of engine power on highway and limp mode due to 2 leaking injectors. Leaking injectors can cause rich and air mass codes as the ecu tries to compensate.

The dealer tech suspected leaky injectors from the start but said they have to follow bmw testing protocol. When the check engine light went away after the MAF sensor replacement they still suspected there were leaky injectors but told me their hands were tied on injector replacement under warranty due to no codes.

I have a ‘14 completely stock and this happened recently with 38k-39k miles on my car. Not saying this is definitely your problem but sounds similar to what I experienced. HPFPs are also a known issue and also have an extended warranty.