what causes vehicle not to start after normal driving?? on 1991 Chevrolet S10 Blazer

1991 chevy blazer s-10 4.3 v-6 truck was running prefectly well went home after a day of driving shut the truck off went bact to crank but will not start..vehicle is getting fire and gas but will not start

Asked by for the 1991 Chevrolet S10 Blazer