I bought a 00 Mitsubishi Montero Sport 3 months ago it ran fine but needed a tune up (oil change, filter, spark plugs and wires) in the process they noticed my valve cover gasket and intake gaskets all needed replaced so its all back together starts right up sits in any gear (park, drive, reverse etc) just fine but soon as it actually starts driving it stalls! Any ideas on what's wrong with it?

 

Check all the lines and make sure nothing got cut or kinked during the repair work. Sounds like a fuel delivery issue.