I have the same exact motorhome you do. In October 2005 I had the same problem. It turn out to be a rotted rubber fuel line going from the gas tank to the generator. I had Redlands Truck repair it for me. They had to drop the gas tank to replace the hose and the bill came to $235.00. They gave me the old hose and I did a lot of research. It turns out National should not have used this hose because it was not intended for fuel injection use and my generator is fuel injected. The coding on the hose showed Gates M08100. I emailed gates and they responded stating the M08100 is a 4219G Hose and not intended for fuel injection. I forwarded all the information to National and they reimbursed me for my costs. I will send you a private message and forward the email messages between myself and Gates as well as a copy of the letter I sent to National RV. Since my incident, another person on this forum had the same problem and I gave him the information. National RV (Matthew Margolis) denied ever talking to me.
2003 Dolphin L/X 6320