Hello, new to the stangnet party, but I had been troubleshooting a smog failure here in California for the last month, or so. The car was flagged by the referee for "data irregularities" and unfortunatly failed that smog check. Now the fun begins. The failure was the 25/25 test for NO, way to high. So that is EGR and Air pump. Pulling the codes with my almost 40 year old Sunpro scanner, found at first 34, 44, and 94. 44 and 94 were for the thermactor system, 34 for the EVP to high voltage. The 44 and94 codes were easy, as the crossover pipe between the heads was pretty bad, and I was able to find NOS TAB/TAD solenoids on ebay. I figured that the TAB/TAD solenoids being 39 year old electrically checked okay (voltage to and a resistance check), but inside the diaphram assembly might be bad. Changed both, and the code went away!. One problem solved. Now onto code 34. Looking at the issue checked vacuum had 20in at idle, and it is rock steady. Thats not the issue, Pulled vacuum at the EGR, the engine would eventually die, but it would take a little time to do that. 39 year old EGR on its way out. All the vacuum lines from the EVR to the EGR had no leaks, but they would get shorter everytime because the plastic is hard and brittle. Fixed those too. The EVR was next. Power and ground were good, the solenoid would light up a test light for a second doing the KOEO test with the scanner. The EVP was giving me fits until I check resistance and found it way high. That could be causing the code. So changed the EGR,EVR,and EVP, AND THE CODE KEPT COMMING BACK! Back to the drawing board. So Monday I got down to the electrial wires checking for voltage change at the EVP and found that the closed voltage was in range of ,26 and .67 volts (.51 to be exact). Thats not the problem. Next checked the wires at the EVP, and they were badly corroded. Took and hour or so to carefully remove them from the connector and clean them. Also cleaned the ECM ground in the passenger foot well. Drove the vehicle on Tuesday and came back home to check for codes, the 34 code is gone, but it changed to code 31, not enough voltage! Rechecked everything, cleared the code, and was able to drive the vehicle today for an extended drive, NO MORE CODES! As the referee needs to see the vehicle after repairs I thing everything will go well. I just wanted to tell this story as I say thank you for all the postings that I read through trying to come up with a solution to the problem. That, and my Chilton's manual, came through.