My truck is a 92 f150 xlt, 4x4, 5.0, e40d. I have had the same two koeo codes since I bought the truck. 327 and 328. The CEL comes on intermittently and usually only when the truck is first driven in the morning. I cleaned the EGR valve and nothing changed. I checked the vacuum line going to the EGR valve and it appears to be good (no cracks, and when I plug one end and blow into the other no air escapes). I tested the EVR and it seemed to pass. It had 35ohms resistance between the pins, and when disconnected it had no vacuum at the top port, and when the truck was running I grounded pin 33 and the idle dropped a great deal. I also tested the EVP and the voltage was between 4 and 6 volts. Resistance on the EVP between pins VREF and EVP seemed low, but i'm not sure if I was reading it correctly. I set the meter to 20k and got a reading of 4.06. Book says it can be slightly lower but not greater than 5000ohms. I do not have a vacuum pump so I did not test it with vacuum. Sorry for the long winded explanation. I am getting tired of the light and would appreciate any help. Thanks.