Hard/weak start when warm?

My vehicle starts up perfectly every morning after sitting all night. If I drive into town and run an errand for a short amount of time, when I come back out to start it up, it will start weak or long crank. Sometimes it’ll stumble for a second and then it’s back to running normal. I’ve replaced my idle air control valve, spark plugs, cleaned my MAF sensor, replaced engine temperature sensor and has new fuel injectors as I suspected it was maybe a leaking injector. If the truck sits for a long period of time, it will again start up just fine.