rough running engine or a stalling condition. on 1995 GMC 1500 Pickup

Hello, I have a 1995 GMC Sierra Truck 5.7 L engine with a rough running and stalling condition.
I have replaced all sensors related to the problem, replaced the EGR valve and the computer. Replaced the spark plug coil and given a total tune up. I'm at the end of my rope. I'm now suspect a distributor problem. I have never worked on a distributer before. Please Help!

Asked by for the 1995 GMC 1500 Pickup
95 honda odyssey runs rough when the air condition-air is on.