Thanks for the reply. When I read it I realized I never posted what fixed the knocking on mine. A friend of mine also had issues with his fuel lines that caused the knocking.
Turns out it was the heat creating vapor lock. They cut out a 10"x10" square where the exhaust pipe from the gen drops down and fabed a box for the air flow to escape. Before they did that the air flow the gen pulled in had no where to go and was heating the gas lines because the underbelly is enclosed. Now it's like a blow dryer blowing hot air through the box they installed. After seeing and feeling that its crazy that hot air flow had do place to go. They also replaced the fuel pump, adjusted the valves, and replaced something else which was part of a recall.
Cummins did all the repairs but I had to have them work through a local FR dealer so they could work with FR. FR ended up covering all of the cost for the repairs. All in all its a bad design by FR when they enclosed the underbelly IMO.