HI Jerry

If there is no feeling like the ABS is coming on to soon or when not needed then I would go with the master cylinder myself. Seen many cause this very same complaint. Sounds like it is intermiantly by-passing one of the seals in the master. Mr. Boggs whooshing/hissing sound would indicate a leaking brake booster for sure which is normaly accompied by a high and hard pedal that takes more effort then normanl to stop the car.

fasthair