Hard starting issues

My car has days where I can hop in and it starts and runs all day. Then the next day it will not start without spraying starter fluid in it. And some days it will not start even with spray. It seemed like it started getting worse when the weather got hot, but then some days it ran and started fine when it was one hundred degrees, outside.
I have replaced the fuel filter, engine temp sensor and PC valve.
There is a buzzing noise coming from the throttle body when I turn on the key, before starting.

Any help would be appreciated.
Thank you