1998 Chevrolet S-10 truck 4.3l rough running at operating temp

I changed the EGR valve, both O2 sensors, MAF sensor and three vacuum lines on the drivers side under the hood. Each sensor was changed after getting a code on the scanner. The truck runs great when cold but after reaching normal operating temp, runs rough, surges and loses power. I am no longer getting an error code. The service enging light comes on after it begins to run rough at normal operating temp. The air cleaner element is clean and new.

Paul