check engine light on on 1996 Chevrolet 1500 Pickup

The check engine light came on and took it to Autozone came back with two codes PO300 and P1406. So I replaced the spark plugs and wires. I also cleaned the distributor cap and replaced the rotor and the coils. I then cleaned the EGR value but did not clean the port and replaced it with the same gasket. How can I clean the port holes and with what. Had the codes earse took it for a drive and the light came back on. Check the codes again and they where the same ones. Don't know what to do next, please help. Sam

Asked by for the 1996 Chevrolet 1500 Pickup
1 answer
P0300 is random cylinder misfire, P1406 is an EGR related failure which can definitely cause multiply cylinder misfire. Read this article it is very helpful. http://www.engine-light-help.com/egr-valve.html