Thanks for the reply. In my research I've read about this too. I think there was a guy with a om606 G Wagon that talked about this issue and added a inline pump back by the tank to help with this issue. I think this is a legit theory and I thought about adding a pump, but held off for the reasoning that it ran well for so long, then degraded to what it is now. Maybe I'm just being stubborn in thinking it should run well in OEM configuration