Engine cranks consistently.
some days i wont hear the fuel pump run for 3-4 seconds to pressurize... cranks great but no start. Repeated attempts, no love.
other days i do hear the the fuel pump run for 3-4 seconds, cranks and starts 1st try.
All lights and accessories work when ignition on, every time.
Car runs fine when starts. No hesitancy at any speed. Has never outright died while driving.
replaced the main relay under drivers side dash, no positive effect.

Ideas?

 

The ECM and main relay are used to supply power to the fuel pump. The ECM needs to supply the ground to the relay coil to energize the coil; so, that the relay contact closes to allow power to the fuel pump.

You may want to remove and open the ECM to check for blown or leaking capacitors; or bad resistors in the PCM. If they are bad, they can be replaced.