Toyota MR - 2 91 turbo

I recently took my car to a repair shop for a leak in the water hose from the radiator to the engine. I have had a recurring problem for several years. When I had repairs done last summer, they tried to fix the problem and thought it was a vacuum issue. It was not fixed. When I drive the car and I punch the throttle in 3rd, 4th, or 5th gear. The turbo starts to wind up. At a certain point the engine acts like it is not getting enough air, I think, and starts to lose power. The spark plugs indicate too much gas.The repair people do not have a solution yet.
One MR - 2 person who has worked on his car, says it could be the TVIS butterfly (it has 8 air ports?) when the MR-2 starts up only 4 of the 8 ports are open. When the turbo reaches 3500 to 4000 RPM, it is supposed to open the other 4 ports to put more air into the system.

Does that seem reasonable?

Vernon