Brat, reread your post and could offer a suggestion. Since you are running only on your aux fuel tank, you may simply be out of gas. You don't say what year your rig is but assuming it's older, you will have a relay that switches off and on to switch over the tanks. At least my older Pace Arrow did. This relay could be bad. I would get 5 gallons of gas and put it in the aux tank and see if it fires up. Good luck...D