Egr valve problem

Hello everyone, I am new here. I need some help here with my truck, this is my first Ford that I ever owned and just having a bit of trouble with it. The EGR valve does not want to work and the truck pings bad when going uphills of with a load on it. I have a 1994 Ford F-150 with a 5.8 EFI with a E4OD transmission 4x4. I already checked the EGR valve itself and found it to be good. I checked the EGR valve control silonoid and with the truck running I have a constint 12v supply to it and the pcm controls the ground. I can apply my own ground to the silonoid and it when activate and snap the EGR valve open and the engine will die. So I know the silonoid is good. I unplug the silonoid valve 2 pin connector and place a test light bulb between the connectors and test drive the truck or even rev. the engine in park and hold about 2000 rpm and the bulb never lights up. The question is why does my computer not suppling ground to control the EGR valve solonoid?? I checked all my grounds going into the pcm and all checked good and even replaced the pcm. The computer just does not want to supply ground the the EGR silonoid the operate the EGR valve anytime...I know the pcm has to see certain inputs before it can open the EGR valve, just not sure where to go next.......