i have a 2002 blazer with 4.3 motor, today i had an over heating problem got up to 250. blazer died, let it cool down when it started it ran real rough and had no power. drove it a couple of miles died again. let it set for a few minites, started it again drove a few more miles died again. traliored it home. truck will not start, turns over just fine, checked fuel pressure its 50#, checked spark got plenty. but still will not start. any ideas will help, thanks

 

check your ignition coil
wean hot

 

Run a fuel leakdown test...key on engine off you should have 60psi and no less than 55psi after ten mins.
Spark should be brilliant blue/white. Yellow/orange spark will not work.
As for overheating ;
Start with the basics. Exchange the coolant. Be sure to burp the system. Next step would be to replace your thermostat.
good luck

 

found the problem it was the cam positioning senser in the distributer, rplaced it truck starts and runs fine again.