i had the harness replaced two days ago having to pay only labor as the dealer goodwilled the part. the engine still exhibited the intermittent rough idle, surge, and hesitation. also, i rechecked the system for faults and the 009 hfm was still present. i replaced the amm today and am amazed at the performance i was missing! having only had the car for two weeks and it being my first w124, i think i'll keep this one for awhile. thanks again to all that replied.