Clutch issues

1988 toyota supra turbo with 120,000miles but with a rebuilt engine with about 4000miles, and 5 speed manual.

1. When the clutch pedal is depressed the transmission will not shift gears without grinding, also when you let off the pedal, it does not come back up on it's own, you need to flick it with your foot. All fluid levels are fine and there are no leaks, any ideas on what the problem might be there?

2. When driving on the highway, if I have to accelerate hard, the car will accelerate and then will jerk lightly, and while it jerks the speed seems to climb more slowly, the air filter is clean, and the fuel injectors should be new as well.

thank you for your help!