My name is XXXXX XXXXX will answer your quesiton. Any Ford Dealer should be able to work on the engine managment system on your RV. Its usually a matter of them having the room to work on it (most shops dont have a large bay for RV's) Bob Bell, In Glenn Burnie, MD used to service them, not sure if they still do.
First I would pull the codes and see what code is stored and follow pinpoint tests for it. I have seen fuel pump issues and also seen a few of the rv's the lines were pinched above the fuel tank and it restricted the fuel flow and caused a lack of power. Unless there is a mechanical concern, Most likely the lack of power is either caused by intake restriction, exhaust restriction or fuel pressure being reduced.
I have learned from multiple sources that the problem my be the throttle position sensor; apparently a problem on Ford V10's. I have found a replair shop (non-Ford) that will look at the problem. I assume they have the code reader, and, yes, it should point to the problem. Are there codes / sensors that will indicate a throttle position sensor problem?