What will cause my 99 Sebring Lxi Coupe 2.5 to stall and not want t o restart

You will need to hook up a scan tool and look at real time data to see what's going on. You could check fuel pressure to see if the fuel system is able to keep up with demand (Long crank times?). There really isn't a fix I can give without more information. You could take it to a mechanic to diagnose then fix it yourself if you are unable to diagnose yourself.

AGREE WITH #1 AND POSS CRANK SENSOR