I have a 2007 530d. The car drove fine for a week or so. After i brought it And then started to lack power low down. Until around 2000rpm. I was told by a garage to replace the maf. Which I got a brand new one. This didn't seem to help at all and the power loss and juddering stayed the same. I have since pulled the mag sensor plug and the power has returned. All codes read and was only one for the maf. Which I plugged back in and has been cleared.
I did notice a sort of clicking sound coming from the side off the engine. I pulled the air pipe off the egr and the noise stopped. And power has returned a little. But I don't think as much as when the mag was unplugged.
Any one with a idea. Starting to annoy me now

 

Leaky vacuum line someplace?

Some have said this has caused you type of issue.

Do you have any carbon built up in the egr valve body?

 

Been so busy with work I haven't had chance to take the egr off yet. But I will be very soon and giving it a good clean. Just to make sure.
I have seen it mentioned about people having similar problems which was down to a vacuum leak. So will find out what size pipe I need and then replace them any way. For peace of mind