91 GMC Sierra running Rough
 

I have a 91 GMC Sierra 5.7L that surges when at idel and cuts out when acceleating with no power. It runs better when warmed up but not good. I have changed out the Plugs, Distributor Cap & Button, EGR valve, Map Sensor, coil and distributor modual. When I change out the EGR valve, I forgot the to plug in the map sensor to the carb and the surging stop. The reason I change out the map sensor, but I still have the same problem with the new map sensor.

Have you checked your grounds and fuses and relays?