1990 cavilier has shut off three times in normal driving then restarts 2.2 eng

These cars are notorious for overheating issues, and can be shut down by two particular sensors when this occurs, one is the coolant level sensor located in your coolant reservoir, another is the coolant temperature sensor, which also activates your engine cooing fan on radiator. Make sure you are using the proper type of coolant also, this model may require Dexcool coolant which is red in color instead of the standard green.

Do not use the red Dex-cool, this coolant wasn't available until 1996 or so and will eventually solidify into a jelly and cause all kinds of issues. I've had customers come in with everything from clogged heater cores to plugged radiators with this garbage coolant. It's more than likely a coolant temp sensor, as it is telling the car it's too warm and about to overheat and cause damage so the car shuts itself off to avoid damage. Use the green antifreeze only.