The thing with problems like these is that you could be looking at a single fault or a group of problems that are each giving you a different symptom. Something could be getting hot in the engine management system that is causing the vehicle to shut down, and a good place to start looking would be the crank-angle sensor. When these get hot, they stop sending a critical signal to the engine’s computer and it just shuts down. After a short cool-down period, the sensor can often come back to life and away you go again.

Meantime, a stuttering idle and inconsistent engine speed on start-up would make a lot of mechanics check out the stepper motor which is part of the throttle mechanism and is responsible for setting the idle speed and allowing the engine to start.

Has your mechanic scanned the car or simply done a few basic checks? An electronic scan should be your next step if it hasn’t already been done.

Barinas were noted for their electrical problems. It could be an earthing problem, or a wiring problem, the only way to find out is to trace it through the wiring loom, or enlist the help of an auto electrician.

Those early Barinas were prone to oil leaks. I guess that you have had it repaired before, but without success. If it's fixed properly it shouldn't leak, but it could be that it needs a better sealant, or the surface of the rocker cover might need machining flat.