1999 Acura Integra Clutch Questions

This problem just start two week ago, the car start to stalling when I try to park backing up into the parking space and again next day when I am going to work. Then when I just get off from highway I put car in neutral and let it stop at end of ram, then it try to put it into first gear but I can not so I try reverse again I can not put it into reverse. After couple try finally in can shift in first and heading to work and again that late afternoon going home I can not shift into first gear or reverse. My co-worker work by and told me to turnoff engine and put into gear and start, yes it work so I heading to garage to have it look. The mechanic said he found that the master cylinders is link and need to be replace and the fluid also is dark color. So four days ago I have the same mechanic change a new master cylinder he also check the slave cylinder and he said it work find. But when I pick up the car he said when one of his mechanic trying to take for road test he can not put it into reverse so he came back in and have him go out and take a look. Again he can not put into reverse either. After couple try he able to put into reverse and then first for road test and it work fine he said maybe it still have some air in the system which is why it made that problem. He said if it happen again may I need to replace a new pressure plate. After I took car home the clutch pedal was smooth and soft going in like never before. But the next day when I am about to leaving home I cannot put car into reverse or first. So try turnoff car and try put it into reverse but I cannot either but finally I did, so I start the car but now I cannot take it out from reverse. I turn off the car and finally can shift back into neutral then I try start car again and now I can put into reverse and then first. But when the car come to stop and I put car into first and give a gas car start to stalling so I give more gas just to keep car going. Now the pedal pressure when I push it, is back to before car is fixing which is free about one inch before feel the pressure. I this mean I still have more air in the system or I do really need to replace the pressure plate? If I do need to replace pressure plate what else I should request to replace too?