Idle Loop, Bucking, Hesitation...HELP!

I've got a '95 GT all stock. My idle loops and at the light I hesitate and buck when accelerating. It also bucks once in awhile cruising. A month ago I change the airfilter, sparkplugs and fuel filter. Check engine light says TPS voltage low, MASS AIR high voltage, MASS AIR low voltage, fuel pump circuit open.
I have changed my TPS and it didnt do nothin. I then cleared all the codes and started the car waiting for the light to come on. When it came on I turned off the car and the computer read MASS AIR low voltage. If I had left the car running all four codes would have reappeared
Could this be my problem? MASS AIR is expensive. Has anyone had similar problems?

I have tested the wires and the mass air. Mass air has a low output reading. It should be .6-.7volts but it reads .07 at idle and it shouldnt pass 2.0 volt at higher rpms but it reads 2.2volts. Very weird. One mechanic said it was the EGR valve but he cant tell me why and the there are no codes for it.

Just for reference, I changed the mass air sensor and it works just fine now.