td4 maf sensor

hi all its me again i am still having probs with this td4 the problem is the engine managment light came on last night and it felt like i was driving a tank. so this morning i have removed the maf to check the make and all i could find was the code pbt-gf-30 is this the correct partnumber ? i also run the 4x4 without the the maf sensor connected and it wouldnt even rev is this right. ? so to sum it up the 4x4 drives the turbo spools at 1200rpm after i reach 2800rpm it slowly kreeps up to 3500rpm and then your wipping a dead horse so to speak. this isnt normal and i left the garage saying he wouldnt be seeing my custome anymore so its up to me to sort. ANY IDEARS