2006 e53 3.0 hesitiation little to no power

[mendes9]

Hello, while driving my x5 today I noticed that I had little to no throttle response and hesitation/engine hesitiation. It got so bad I was down to maybe 10 mph but I was able to barely make it home. It threw some codes that I was able to pull with my generic reader which were p0171,p0174 and p1515. I know what they are except for the p1515 which is I think a manufacture specific code only read with a better scanner.

My first thought is Mass Air Flow sensor.. I took it out and cleaned it, but it didn't look dirty. I thought maybe it's the transmission but putting the car into neutral did the same thing no change when it was happening. When it wouldn't accelerate I had put the pedal down almost to the floor at one point and the engine did accelerate at one point but I heard what sounded like a knock in the engine. For throwing lean codes in both banks, means to me possibly has to be some sort of sensor. These engines have individuals coil packs on each cylinder right ( I replaced the plugs around 60K miles, have 88K miles now) so the way the engine was hesitating it had to be more than one cylinder. Is there maybe some sort of central coil pack that controls all of them? Any suggestions would be welcome before I take it to the stealership.