Car will sometimes keep running when key pulled out, and engine will sometimes stop while driving. Will start agaain after waiting 10-20 minutes, Replace ignition switch???

 

clean the contacts and see if there's a difference or just replace since it's a known issue.

DIY Ignition switch cleaning - Team Integra Forums - Team Integra

if not here's other likely suspects:

Honda Acura Essential Electrical Repair Website. Troubleshooting Main Relay, Coil, Igniter, etc.

 

It is typical on old cars for the key and cylinder to get worn enough that you can pull the key out without turning it to the off position.

When the switch is bad causing the car to stall, you can usually re-start it immediately. If the engine stops while driving, and the "oil" and "battery" lights on the dash DO come on after it stops, the problem is likely not the ignition switch. If the lights DO NOT come on, the switch could be bad.