Code 11 Momentary interruption in power supply to ECU (electronic control unit or computer) up to 1991.
As for the boost issue, you may a leak somewhere in the IC piping, but I would start with looking into the Code 11 first... the ECU cutting in and out will cause the same sensation as it's doing the same thing that happens during fuel cut.
When I first saw this thread I thought you were saying that the actuator had died... knock on wood.
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