Jeep won’t start

I have a 04 Jeep Liberty 3.7L V6 2WD with over
200,000 miles. Whenever it’s early in the morning or
early afternoon my car will start up just fine but after
sitting out in the heat of the day it takes quite a few
try’s for it to start. There is no light coming on for
me to test what code it’s throwing. I’ve had the
alternator, start, battery and all that tested. I’ve
replaced the ignition switch, actuator pin and even
the lock cylinder and it’s still doing the same thing.
Every thing turns on when you turn the key except
for the car itself. I have a feeling it’s something
electrical or something that’s not an easy do it
yourself job. I’ve asked a couple shops and they
say it might be the ECM or a lock cylinder housing. I
prefer doing the job myself over taking it to a shop
to be charged out the wazoo but I’ve done
everything I thought it could be. It just doesn’t like
the Texas heat. I’ve also read a couple answers to
similar questions and they say it could be fuel
related