Driving for about 20 mins & stop at the light the car cut off?

Hello,

Anytime a vehicle sits for an extended period of time, there could be a number of items that can go bad.
This issue could be due to a vacuum leak, dirty mass air flow sensor, dirty throttle body, worn out spark plugs, wires, clogged fuel filter, clogged air filter etc.

The best course of action would be to inspect all those components and make sure everything is in working order. Check for any vacuum leak, clean out the mass air flow sensor as well as the throttle body.
Replace the fuel filter, air filter, spark plugs etc.

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Is your check engine light illuminated? If so, retrieving the codes can help with the diagnostics.

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Please let me know if you have any questions.
Thank you.