RE: 93 blazer dies while driving
I'd say check your ignition coil, ignition control module, distributor cap, rotor, and fuel filter.
Sometimes when the truck gets hot, all the trash in that filter will gum it up. Next time it does it, tap on the filter and the bottom of the gas tank and see if that makes a difference.
While the truck's running, carefully pull the boot off of the coil wire and see if the coil is firing, if it is, make sure it's a white/blue spark and not red.
The ignition control module will also cut the truck off when it gets hot if it starts to go bad. Those can be tested at your local AutoZone, just have to get to it. It's plugged into the top of the distributor.
Those are all places that I'd start. Start small and work your way up.
1997 GMC Sierra Z71
Spark It or Park It
In Loving Memory of Matt Jones
12/30/85 - 11/06/05