My brother has a '92 S10 Blazer 4.3 Vortec V6. Drove home from work today, ran fine according to him ( Plus I saw him drive in and seemed to be running fine ). He shut the truck off, and about 45 mins later he went to leave, it wouldn't start. It cranks and has spark. I've worked with cars for 15 years, but am still getting the grasp of fuel injection. Carbs are my specialty. I think it's the relay, because I don't hear that "click" or the whine of the fuel pump, or maybe a fuse? I could really use some help, thnx in advance.