. My car has been in the shop for 3 months and he's out of ideas. Any suggestions?
Take it to a different shop.
I replaced my master cylinder a few years ago.
To bleed the system completely of all air, here is what I did after suffering thru the same symptoms you have.
Jacked up the front end, went under the car and removed the slave cylinder from bell holusing.
Removed cap from master cylinder and put a towel around the cup. Back under the car, I took a long, large philips screwdriver and pushed the slave piston all the way in. This caused the master to purge much fluid out of the cup. Released the slave, filled the cup, and repeated pushing the slave piston in. Did this 3 times.
Next, Filled the cup and put the cap back on master, re-assembled slave to bell housing and hooked clutch back up, had the wife jump in the car. Had her pump the clutch 20 or more times andf on the last pump/push, hold the pedal down. Bled of the slave, closed the bleeder, had wife release clutch pedal.
Clutch works as if it just came off factory floor.
15 minutes/ done.