2000 Alero idles low and dies when stopped.

fuel pump and filter

Check fuel trims at idle for direction. High fuel trims usually imply a vacuum leak but could be other.

Clean throttle body and idle speed control valve.
Re- learn the idle speed control valve.

Have you at all serviced the automatic gear box? one possibility is the gear box.Also the vibration is either broken gear box or engine mountings broken or weak.

Could be a dirty throttle body or a faulty idle air control valve.
Is the check engine light on ?

oxygen sensor

check your vaucumn hoses for leaks any leak in that system will effect your fuel pressure regulator and fuel rail that controls the running ability

You don't have right AIR: GAS ratio of 14.6:1 at idle. If you don't have idle adjustment, you need to have throttle valve clean.
If it doesn't work, then your Fuel Distributor is drifting out of calibration.
Don't worry about check engine light comes on when the engine dies. It is designed that way.

My 94 Sedan DeVille had the same problem. The car ran great but would stall whenever I stopped at a stop sign or traffic light. Turned out to the the TPS (Throttle Position Sensor). It monitors and controls the idle. What happens is the secondary idle (idle when the car is warm) is too low. Since all the controls for fuel mixture, idle etc are done electronically, they can't be manually adjusted. The TPS is the most likely cause of your issue. A diagnostic test (performed free at most chain auto parts stores) will be able to confirm this or lead you to another component. Best of luck to you!
Greg

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