Blazer stalling
 

My 87 S10 Blazer stalls out when it is idling or is at a stop. The engine surges a few times but usually shuts off too. I have done about everything you could think of to see what is wrong, but nothing has shown up. My only guess are the temperature sensors, the speed sensor, the distributor, or the computer itself.

I've done everything concerning the egr valve, checking for vacuum leaks, and ignition. Any other suggestions will be helpful.