might try getting a vaccuum gauge that fits in your gas door. I haven't seen too many but I know they're out there. That will tell you if you if the pump is working right, if it builds pressure then the vaccuum will be there too. It sounds alot like a TPS though. If you can find one from a buddy and put it in to see if that works. Those little guys can wreak some real havoc. I mean they do some weird sh*t sometimes. But for 75 bucks it's too expensive to guess on. Good luck.

Shit is all apart. Typical...