1993 Jeep Grand Cherokee Hard to start

93 GC Limited 4.0 is hard to start

if I just turn to run position I will not start

if I turn to on 3 times then turn to start it fires right up and then shut off and then start right up on first crank

but if it sits for an hour or over night it wont start

ive changed air filter, oil filter, oil, fuel filter, fuel pressure regulator, plugs, wires, cap, rotor

next is either o2 sensor, crank or cam shaft sensor, feul pump, or ecu

not sure what to do

any help would be great!