Buick 3.1 no fuel pressure

Hey All,
This is my first post on this board but I have had much success on similar boards so I hope you can help me out here, nobody else can. OK, so my daily driver is a 1997 Buick Century Custom with the GM SFI 3.1. The car has about 70000 miles on it. About two weeks ago, before I left my job at Auto Zone, I bought a bunch of sensors and such for my car at a great price. At the current time, none of the sensors were bad and the car was running pretty good, but I wanted to freshen everyhting up so I changed the MAS, MAP, Air charge temp, IDle air control, TPS, EGR, and the Fuel pressure regulator. After I changed all these things and cleaned up the plenum and put a new throttle body gasket in everything was running ok. I hoped it would run better but I figured the ECM just needed time to adjust to teh new parts. On the third day after the change I started it before going to work and I noticed it was running kind of rough. Not like it had a misfire but like it had a big cam in it. On the way to work, all highway, everytime I would let off the gas and then hit it again the car would jerk violently and then accelerate as usual. Not downshifting, just putting my foot back on the pedal. After work I started it and noticed the idle was really high, probably around 2500 or so. In gear out of gear in neutral it didn't matter, the idle stayed high. After I got home it was still idling high so I figured maybe I got a bad TPS, so I disconnected the harness from the sensor and started it. The idle was low, and then it died as I had imagined it would. I plugged teh sensor back in and turned the key but it wouldn't start. There was no prime in the fuel pump and accordingly no fuel at the engine. And it sits in the same spot now. Every few days if i go out to start it it will run for a second or two one time and that is it, but the fuel pump still can't be heard priming and the fuel rail remains at 0 psi. I talked to a bunch of people and heard everything from guage cluster to ecm to fuel pump. I figured those were valid as I could have spiked something when I unplugged the sensor. The problem, however, is taht all the fuses were good, none melted or broken and the I changed the relays. If a fuse or relay didn't go, how could the computer or pump spike? I heard that I should check the thick grey wire at teh pump for 12 volts at the harness. Was going to do that today but got scared. I can see the wiring harness to the pump, a cluster of six or seven wires. I also see, however, that the harness appears to plug into an insulated clip next to the spare tire hold underneath the trunk. I lifted the trunk carpet to see if the wires came through but I couldn't find them. Do the wires to the pump run inside the car instead of underneath? And if I hook a test light up to this black clip under the car with the pump harness unplugged to see if it lights during the prime period will everything be ok? Or should I just pull the wire out of the harness at the fuse box in the engine compartment and test it there. Usually I can fix anything on a car but this one has me lost. Am I just missing something under there? Any advice would be tremendously helpful as my firebird really doesn't get good gas mileage and that stuff is expensive. If you need more info let me know, I can probably give you anything you need. Thanks all.
Tony