Thanks everyone. I'm glad to hear the consensus on more bleeding needed and on maybe a master cylinder problem. The pressure and preload might indeed be adjustment needed in the master but I have also heard that that slave cylinder has a check valve that could do similar things. However, presumably a slave cylinder problem is big repair bill since it is internal to the bell housing. I'm going to take a spare master cylinder to a Miata specially shop where I hope they will work on the car and confirm that this is just an adjustment or master cylinder problem. I have heard that this clutch is not a standard Miata clutch but a high performance type.
