Landrover td4 bmw engine

First of all i like to say a big hi to the members.

Now my problem with my landrover td4 [Bmw engine]The problem is
im getting loss of power on at like 50mph or more.i have read about the maf sensor and i did have a test in my local garage when the car was running fine it was registering 10 but when it was playing it it was going down too 4 now i have seen a post saying to use Pierburg Maf instead of the bosch one. now i fitted the pierburg maf and its gone realy bad now on bottom end where it used to be ok i was wondering is
the pierburg 7.22684.07.0 work on my type on engine and if you think its not that part gone what do you think it is. thanks

if you do a search for roverron, or synergy 2, or go to:

Tuning-diesels for cheaper diesel tuning.

and have a read through, all should be revealed.

might be worth having a read of this too:

http://www.landyzone.co.uk/lz/f9/td4-lack-power-70mph-fixed-77147.html

good luck