Why does my truck hesitate while accelerating?

The check valve in the fuel pump may be bleeding down after sitting for a while. To check to see if that is the case, first thing in the morning turn the key to the on position (no crank) for 10 seconds and then off. Repeat this 3 times. Then start the motor and see if it runs as it should. Doing the key sequence allows the fuel pump to run and prime the fuel lines with pressure. If that does the trick you don't need to replace the fuel pimp, it's not going to fail. Just realize that you need to do this trick after the vehicle sits over night or you may wear the starter motor out prematurely from the extended crank time.

An OBD2 code check will tell you more than we can. We can guess and suggest spending a lot of money on things that probably don't need replacing, but the OBD will tell just what is malfunctioning.