Well, I changed the fluid again this wknd and same results. It has been above normal in temps outside here in Ohio, but today was first time where the car sat out with temps below 30 all day. When I drove off and at my first stop only 200 ft away, as I pressed on pedal, it went down, started to stop and then continued on for a bit more and then stopped again. Did not do this again. I am going to try the brake booster check valve first and then master if that doesn't do it. More to follow. How do you bleed fluid at master? Is it the two bleeder screws just below the fluid holder?