poor acceleration loss of power

[kreeed1]

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!!