Tps....
If the machine starts and runs, I'd say it's the TPS. If it were the ECU, I don't think it would run like you say it is. Have you looked down there by the air induction system, where you put on that new air intake from RIVA to see if that plug is loose?
The shop is going to charge you about $90 bucks an hour in labor charge. That's a standard rate in these shops. If you can check out a couple things yourself, you may save a bundle.
Do you have a friend that can interpret readings from an Ohm meter?
I hate to see you pay $400 bucks for a $50 dollar job.