[x5m5]

So picked up a 2015 50i with 81k miles about a month and a half ago. Car has a race chip gts installed. Been driving it pretty hard and now am at 83k miles and just got a drivetrain malfunction with a bunch of codes. Cylinders 1-8 occasionally show up but the main ones that show up every time are

11A002 high pressure fuel plausibility, pressure too low

11B401 high pressure fuel on or after the release of injection too low pressure

11B501 high pressure fuel in or after the release of pressure too low

When I just have these the car still drives moderately ok but still does show up immediately after a reset.

Then occasionally these show up and the car is barely driveable

118501 Mixture Control 2 too lean: excessive deviation

11b701, 119F01, 11Cf31 which all releases to mixture not being right

I tried to revert the tune back to stock which was installed about 2 years ago by previous owner. Car drove great for first start then back to severe limo mode on the following start. Spark plugs were changed about 15-20k miles ago.

Tried doing a search but couldn't find where to start. My guess would be Maf first otherwise maybe fuel pump? Any input would be appreciated