ford f-150 battery drains after it sits for a few hours with nothing left on,while charging battery and i try to start truck before a full charge it turns over but not start and after i take key out its tries to start on its own. i do have auto start but i turn it off. i checked the battery and its fine,starter its fine, i disconnect the battery after i started it to check the alternator and its fine. truck runs great but drains battery dead when it sit for a few. please help.

 

To suck the battery down in a few hours mean you have a pretty big draw. It's probably bigger than the Average DMM can handle without using a shunt, I wouldn't recommend using the ammeter just yet.

Since you mentioned Auto Start, I assume it's some kind of remote start system. It's possible that it's got a failing relay, and feeding power to the ignition circuits. I would start with the wires under the column. Check the ign and accy wires for current, then pull the fuse for the autostart and check them again. If they still have voltage try adjusting the ignition switch.

 

Here's a good way to track down a drain. Get a cheap testlight and hook it up like the diagram below. If it glows bright, you do have a drain. Since you have a later model truck, you might need to close the doors and let the accessory delay relay time out before you start checking for the drain.

After the relay times out, and you have a drain, you can start pulling fuses one at a time till the light goes out. If it never goes out, take the wires off the alternator. If the light goes out with the alternator wires off, you alternator has a problem, even though it's charging the battery when it's running.