My car starts but will not stay running at idle. Why is that?

There are a few possible reasons why your car would start but then stall at idle. One possibility is that there is an issue with the fuel system, and the car is not getting enough fuel to keep it running. Another possibility is that there is a problem with the ignition system, and the spark plugs are not firing correctly. Finally, it is also possible that there is a problem with the engine itself, and it is not running at the correct speed. If your car is stalling at idle, you should take it to a mechanic to have it checked out.