Got in my truck this morning with temperature at 31 degrees and went through the normal startup proceedure. I had plugged the block heater in for about two hours. It surprised me that it didn't start right up. It turned over for more rpms than normal. I might add that the truck had sat for about a week without being driven. It ran smoothly once started and I proceeded down the road. Drove for about 1 mile to pick something up for snowblower. Shut off for about five minutes and it took a little longer to start but ran smoothly once started. Didn't go for more than fifty feet when the fire went out. Waited for a minute and it started up. I went through this for three or four times trying to get home. Finally made it to my garage where it gave up again. Left it sitting for 15 minutes and it started up so I pulled in to garage where it immediately died. I've replaced the fuel return hose in the past and there's no sign of any fuel leaking. When I drove it a week ago it ran and started normally. Any help will be greatly appreciated.