Okay here is the problem. Not so long ago (3 months) I had my fuel pump, ignition switch, and a full tune-up done. Now when I'm driving the truck it sometimes just stalls and cuts off without any warning. It doesn't happen all the time just maybe once in a day. I'm cluess to what this could be. Maybe the pump going bad again? Map sensor? Help me out guys. Thanks in advance.

Could be many things. Could easily be a fuel pump, get a fuel pressure guage on there and watch what happens when the truck stalls. Could be ignition problem, crankshaft senor for instance could cause problems like this. Does it start right away after it stalls?
Another good thing to do would be to check for any codes that may be stored.
Good Luck!

Sometimes it does. Sometimes it takes a few times for it to crank. It does however turnover.

Check your fuel pressure, get a guage on there and watch what h appens when it stalls.

When its stalling are you getting the dash lights flickering on and off like its the iginition switch.