What tells the solenoid to direct vacuum to the egr valve?
The 10A ECM/SOL fuse under the dash--- have you checked it? This fuse is also tied in with the A/C relay, the fan delay relay, and the canister purge solenoid. Just something to consider...
The EGR will still operate if the connector is unplugged from the tranny; mine has been unplugged for a couple of years now as I run a 9" AC NLU converter. I live about 90 minutes north of you and I was in a "Test Only" situation as well (aren't they all??) when I had my '87 GN smogged back in April '03. My results were:
15 MPH CO2 14.3 %02 0.0 HC(ppm) 28 CO% 0.00 NOx(ppm) 85
25 MPH CO2 14.3 %02 0.0 HC(ppm) 31 CO% 0.22 NOx(ppm) 42
This test was conducted with 160,297 miles on the original engine with a stock appearing combo that ran 11.1s at nearly 120 with a flat cam lobe. The car had a fresh cat with less than 100 miles on it, 72# injectors, newer R42 plugs w/factory wires, modified stock ECM running a normal (not emissions) 18* timing street chip at 42 psi static fuel pressure, and 10 gallons of Chevron 91 in the tank with no additives from a bottle. The oil in the crankcase wasn't very fresh either. Was I stressing out as I stood looking through the shop's lobby window, watching the smog tech "drive" my car on the smog dyno? You bet I was! When it was over, though, even the smog guy was impressed with the results.
My point: take heart-- hang in there, you'll get through this!
Morgan