Okay, here is the deal. Had some problems with the truck starting and replaced the starter. Truck ran fine for almost a month. Last night, I get in it, start it up and run to the store. Get back in it and NOTHING!!!!! Absolutely NOTHING. Had a friend come and jump it off, and it will not stay running unless you keep your foot on the gas. It will not idle. Today, checked the battery and it was down to 8 volts. Tried to charge the battery and still nothing. Disconnected the alternater, and start it off the battery only, and still nothing. NEED HELP!!!!!!

 

Do the following: get to the throttle body (TB). Take off whatever air filter or whatever you need to, and get a look at the "butterfly" valves. (Engine OFF). Manually open the TB up (again, engine OFF). look down the "throat" and make sure there is no obstructions, and that everything is clean. Clean it if needed.
Now, usually located on the back of the throttle body is whats called the Idle Air Control (IAC) motor (sometimes called the IAC valve instead of motor), and is typically mounted to the TB with 2 screws/bolts. Remove this. You will see its air passage on the top of the TB. The IAC has a pintle that moves in and out, according to what the computer (PCM) whats it to do. Now, get a helper. Have this helper put the key in the ON position. (DO NOT START ENGINE!!! WITHOUT THE IAC MOTOR IN PLACE, THERE IS NOTHING TO STOP THE ENGINE FROM REVVING VERY HIGH, POSSIBLY CAUSING DAMAGE TO THE ENGINE!) You should see the pintle move. Also, the pintle should be clean, as should its passage way.

Thats my best guess since "it will not stay running unless you keeo your foot on the gas." If this is the cause, it will set up back about $50.
Let me know what you find.