Why would a Boost Gauge jump while idling?

Question

I am in the process of trying to find some answers for my roommate who has shelled out thousands of dollars in car repairs, only to experience the same problems. 1994, Pontiac Bonneville with Supercharger. The boost gauge jumps while the car is idling and it sounds like the car is randomly accelerating by itself...as if someone were in park...but pressing the gas pedal. What are the possible reasons that a car would be doing this? We are trying to find out if the source of this and other problems might be attributed to a parts that was supposed to be fixed previously. Any help is truly appreciated.

Answer 1

Maybe the waste gate is moving to a closed position.