We're at a camp ground in Irvington, VA I filled up the truck and on the way back to the campground, it started to misfire and lose speed. By the time we got back to camp, we had a top speed of 23 mph! We'll not make it home like that. I opened the water/fuel separator to dump and nothing came out. I then turned the switch on and got fuel to dump. Now the truck misfires even at idle. 5000 miles on a 2nd generation 24 valve 2002. Help