vacuum leak on the engine compartment maybe check all your old lines any thing that looks old and crusty replace them. maybe needs a tune up also air filter spark plugs and wires
the starter might be turning the engine but is it turning slower than normal? is it struggling to turn the engine? take the car to autozone while its running and have them do a battery and alternator test check with the electrnoic hookup thingy. it will tell you if your battery is good or bad...