Hi All! Love our 258. So now it has no power. I checked the fuel pressure with our scanner. It shows the fuel pressure drop as we accelerate. We changed all the filters. Found the Over pressure valve leaking, replaced that. Ran it off a bucket. Even swapped the High pressure pump with the SCV from another truck. No Change. Just for the hell of it today we clamped the fuel return line and what do you know the fuel pressure came back and now the truck has power! Anybody know what part has failed? Is there some other valve that we missed? Thanks for any input!