If its manual you obviously don't know how to drive it. I have a 1985 Cabriolet and I don't have any problems with it and its been sitting on a driveway for 5 years.
"Stalling while driving" could have a number of reasons. I'm afraid this question is too vague to genuinely answer; more details are needed, but the most likely cause lies with a fuel delivery issue.
Manual cars can be tricky if someone doesn't know how to drive a stick shift one way to see if its you or the car is have a friend that drives a stick test drive your car with you in it.
It might be a clog in the fuel system somewhere or a backed up catalytic converter. It would help to know exactly when and how its stalling out IE at red lights going up hill,downhill around curves. I say this because when a car stalls at different points its symptomatic.
i have a 1992 Volkswagen GTI and it was doing the same thing stalling while driving and we found the it was the fuel pump relay good luck
My 87 Jetta had an intermittent stall problem, even while doing highway speeds it would just die. Sometimes it would restart... sometimes it would restart after several minutes off. I removed the fuse/relay box cover and by tapping on the tops of the relays it would occasionally recover.
It turned out to be the fuel pump relay. It has a control circuit built in, the part that causes it to shut down the fuel pump if the engine isn't running, used to prevent gasoline being pumped after an accident that may have damaged the fuel lines causing gas to pump on the ground.
I had to resolder a few of the connections in the relay and so far it's been fine. The problem was a couple of broken solder connections to the PC board, and it is fixable if you have some experience soldering. Otherwise, get another relay and you're good. There is also a known issue with those cars having grounding problems in the fuse block, thankfully that wasn't the problem.
Since that relay can be non-destructively disassembled, I'm going to check it on every one I deal with in the future, since it seems to be a recurring problem on the gas engine variety of those cars.
I had this problem a few years ago with my 93 Cabriolet and it turned out my steering column was lose. It was a quick inexpensive fix and has been fine since.