Is the clutch going 1991 geo prizm periodically will stall in idle traffic and then can't get it in gear after a restart am able to shift again?
its probable that the clutch is going and the reason why it
works after you start the car back up is your giving the clutch a
chance to cool "if even for a second" and the fingers on the
pressure plate extend back out enough to do you some good....look
into having it replaced.