When my 2000 vw beetle is parked outside for long periods of time sometimes it doesn't want to start then when it start it will keep stopping along the way what could this be?

Your 2000 VW Beetle may be experiencing issues with the fuel system, such as a clogged fuel filter or a failing fuel pump, which can prevent it from getting enough fuel to start or stay running. Additionally, a weak battery, corroded terminals, or issues with the ignition system (like spark plugs or ignition coils) could also contribute to these symptoms. It's advisable to have the vehicle inspected by a mechanic to diagnose and address the specific problem.