car won't start

[keilux325]

sometimes my sons 2005 chev malibu won't start the motor spins over but dosen't start it might do this one or twice a week it has the v6 motor in it we did a complet tune up plugs cap wires air fliter the fuel prusser was good if anyhas had this problem and fixed it or has an idea on whats wrong please let me know that you keith

 

[zora]

when the car wont start, have you checked for spark and fuel pressure?
do you have a check engine light on?
have you checked the wire harness going to the crank shaft position sensor?