poor acceleration loss of power
 

2001 X5 3.0, 195,000 miles. sudden loss of power under 2500 rpms. acceleration is terrible. if i go over 4500 rpm check engine light comes on and truck switches to limp home mode. Idles great. few hiccups while accelerating. No problem to start engine. just driving feels like a 3 cylinder instead of a 6. codes say fuel rich in cylinder 4 or five. switched coils around (4 and 5 with 1 and 2) and codes still say 4 or 5 (one or the other) running rich. things i've done to solve this:
1) new MAS
2) new ccv
3) new disa
4) new intake hoses (elbow from air filter, and connecting hoses)

Could it be coils? ignition unit? Help Please Anyone!!

Have you made sure the fuel injectors are working properly? Are they all clicking on and off? I would check the continuity of the Coils and check the ohms of the injectors. When was the last time you changed the plugs?

Did you replace all those parts with OE bmw, or OEM bullshit from ebay?

How about getting the check engine to come on, and scanning for some codes. That will point us in the right direction.

+ 1 on injectors and plugs.

You mention changing the CCV. I assume you did all the associated hoses with that unit?