Intermittent problem starting the car. Sometimes

Could be a cold start solenoid is intermittent or sensor to it is flaky.

Possible bad ground or battery terminal connector.

could be the shifter when its not engaged in park all the way it prevents it from starting

sounds about right, probably is ignition switch, reason you don't get codes is because if power is'nt connecting to engine while problems occurs then ecm won't pick it up. you should have 2 ignition switches, (the lock cylinder and key switch, the other is the electrical, usually located under the dash, and commonly atttatched to the column close to the firewall, check connections first, it may just be a loose plug in connection

sounds like ignition switch faulty(only faulty when you turn key to start engine??)

Check out the Starter Solenoid Relay, in the Main Power Box.
Regards,DT

have the crankshaft sensor checked.

check the igination switch.
do you get power to the starter???
you need to check first.

Mass air flow sensor.

sounds like the ignition switch isnt signaling the solenoid all the time try replacing ignition switch or test the small wire on the solenoid i think its purple when it wont start with a test light clamp on ground n probe the small wire with key in start posi=tion test light should lite if not i would replace ignition switch