My car doesn't start or has a hard time starting?

I have a 2005 Ford Explorer XLT V6 4.0 Flex Fuel with 126000 miles in it. When staring the engine it turns over fine, then sometimes sputters and stalls. I have to push the gas peddle to keep it alive.
I just changed the fuel filer and put new spark plugs and wires in. I think it might be the gas pump.

You can test the fuel pump pressure very easily. Google it.
Don't just guess and replace parts for no reason, waste of money, but a lot of people do that.

Do you just depress the gas pedal once and then let go of it? That is the way to set the choke flap, as the weather turns colder, there will be more of that actually happening. The car should start right away and run on a fast idle until the engine kind of warms up and then it automatically kicks to a slower idle as the choke comes off as the engine is hot. Before I think pump, I think the ignition timing should be checked by a qualified mechanic and the air cleaner changed. Heck of a lot cheaper.

That would be my best guess. Sometimes when a pump is becoming weak it will not kick in as soon as you turn the key or will not build pressure fast enough. Try leaving the key on for a few seconds before startin and see if that changes the way it acts