What scanner are you using?

The P0102 code does indicate a problem with the MAF. I would start by checking air intake such as a very bad air filter or a crack in the air intake tube after the MAF. I would check for broken or chaffed wires in the MAF connection or a bad ground. It is possible to purchase a bad MAF. I would clean the old one with MAF cleaner and see if that makes a difference.

FYI-The idle control valve can cause a misleading MAF code.

Not saying fuel pressure could not be the problem. Many auto parts stores rent what you need to check fuel pressure.

__________________
X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas