2004 Cavalier difficulties starting

I have a 2004 Chevy Cavalier with 113k miles. It is having problems starting. If it’s sat for a while 10-15 minutes it’s starting rough or in most cases needing me to press the gas pedal to get it started. I have replaced the fuel filter and used some fuel system cleaner to what appears no avail. I can hear the fuel pump turn on at startup, so not sure if that’s the culprit. Any ideas?

Anti-Drain back valve in the fuel pump might be it. Try turning the ignition to START for a few seconds about 5 or 6 times without turning the engine over. You are just trying to get the fuel pump engaged, not start it. Then start the car. If it starts, the anti- drain back valve is leaking.

Above post is spot on, the most likely cause. This can be confirmed with a rail fuel pressure test.

If the engine starts while stepping on the gas pedal, I would look towards a faulty Idle Air Control valve. The IAC valve is what allows the engine to start and idle. If the IAC valve sticks when it gets hot where it doesnt allow air into the engine, and you step on the gas pedal, you allow air into the engine and the engine starts.

A defective anti drain-back valve on the fuel pump takes time for the the gas to drain back into the gas tank. Not 10-15 minutes.