your fuel pump could be bad if it runs for a few seconds .
check your spark plugs
Assuming the battery and starter crank the engine, check for fuel and spark. You are probably missing one of those.
plugs wires
see CarTalk.com
No, it will crank, but it will not start.
first check and see if you have injector pulse if you do try changing the crank sensor its only about a $20 part
it will feel as if you are running out of gas, the car will start sputtering.
fuel pump
Crank no start.
bad crank sensor
depend serveral things , you have to tell more of the problem
wont crank or wont start http://www.kick-fix.com/nostart.html if it wont crank backup 1 page find no crank.