Sounds to me like you may have a vacuum leak. What does the ECONOMY needle do when the car is idling and in gear? It should be pegged to the left when idling, and when you are stopped in gear. When you accelerate (whether moving or stationary) it should move to the right.

I'd baseline it by doing a smoke test, to eliminate vacuum leaks as an issue. Should be 15 minutes of a mechanic's time who has a smoke machine. Do this and report back.