Need Some Answers Please!!!

Ok, i have read through most of these jetta troubleshooting threads, with the related problems as mine. And i have followed the advice given to others and spent too much time on my car. and the problem still exists.
I have a 1994 jetta 2.0. It has an idling/acceleration problem, to where it feels like it is losing power.
First thing i did when i got the car last year (it had half a motor and no transmission and a bunch of missing parts here and there) was tore down the engine (at least the half of the engine it came with) and checked for any visable problems. Then i bought parts to finish the engine. I re-gasketed everything, new mounts, replaced wiring, replaced a lot of mechanical linkage parts, put a tranny and a new clutch and flywheel in and wahlaah!! The engine bay was complete. So then i finished the normal tune-up-- New air filter, spark plugs, wires, injectors, parts of the fuel lines, new (stock) intake, new vacuum hoses, all new fluids, new distibutor and cap, and changed the oil and filter. Now it was time to start it! cranked it over and nothing. Replaced the battery and it started cranking. yet no startup. So i put a new coil pack and still nothing. Thats when i realized i never heard the fuel pump buzzing. So i checked it and it didnt even have one! So i bought a new fuel pump ($487) and a new fuel filter. and it started right up. but it has this idling/power loss problem. So i checked fuel pressure--it was normal, and i replaced the mass air sensor and throttle body. and the problem still exists. I replace all belts and checked the timing, and it was right. problem still exists.
I have checked and replaced the fuel system and its components (including a new gas tank-cuz it was rusted inside), i replaced and checked the entire intake system, and i have also checked and replaced the entire ignition/spark system. I am almost too fed up to work on it, but i am holding onto to hope. The mechanics i talk to are stumped, and the dealerships are charging too much. So any help or opinions will be greatly, greatly, greeaattlllyyyy appreciated.

Thanx

It looks like you've done everything but check the idle stabilizer and the fuel injectors. If the gas was in it for a long time it goes bad and clogs the fuel pump. I'd put in some injector cleaner and clean your stabilizer valve.

I had a feeble idle, with wandering idle r.p.m. that turned out to be due to a slight leak into the air stream, between the air-flow sensor in the air cleaner box, and the throttle body. One tiny vacuum hose was disconnected. If that rubber inlet air duct has any crack in it - your idle will be affected a lot.

I still think you're looking at a fuel problem. Check the pressure when you give it gas and see if it is able to maintain the pressure. If not, the new pump may be gummed up from old gas. For parts, you should check out:
http://www.sasponline.com/
They have your pump for $270. They are just one place of many, but I buy from them all the time.
Check your electrical connections to the pump. Maybe you've got a loose wire and the pump is loosing power. Did you have gas setting in the tank for a long time? This can lead to a gummed filter and pump.

i'm with denisond3...i would suspect a vac leak ...and like he said it doesn't take much.....i don't know if your vent and heat ducts are vacum operated but a vac hose or gasket would act like you say...