02 Elantra GLS

Had a rear converter replaced by mechanic and every since my car is having one thing after the next happen. Had converter replaced and everything was pretty smooth and zippy. One day come down a turn loss all power and coasted to a safe place to stop. Car wouldn't start back up on a half tank for about 20 minutes or so. Finally got it up and running. Took to someone I know. They tell me, oh it's nothing serious.

I start doing my own research and trying to diagnose myself with no tools. I have replaced the coil pack, new plugs and wires, oil change, air filter, and front converter. Put in a new pump in the old assembly and new filter. Think the pump is fine as I hear it when I turn the car on. Just replaced the camshaft sensor. Going to get codes tomorrow cause CEL is still on, but what the heck is making my car not start up right away.

In the morning depending on how cold it will take about three cranks. Through out the day I can crank one time and then turn off. crank again and it fires up.

Where can I start looking into to fix this problem cause it is so embarrassing. I just want to get in my car and go like I used to without it making a fuss. Since replacing the camshaft I just drove straight home like 3 mins away and I noticed it has some power to it, but the starting issue is still there.