Not showing any cel's. Did the plugs a few months back along with fuel filter. Sometimes the truck will start and die automatically, rpms will go up to about one and a half then just die at start. a few tries later and a little push on the gas pedal and it starts normally and runs fine. Wont do it again for days or weeks. But now it does it all the time but doesn't die, Idle jumps up to one and a half then down to about 400 and almost dies but then jumps up to 750 and runs fine. Yesterday idle was high..around 800 when in gear and 1000 when in park. Today its low, around 700 when in gear and 500 when in park. Something definitely doesn't seem right. Also when its cold you can hear the fan or what it sounds like...surging but the idle doesn't, hard to explain but it almost sounds like the motor and fan are surging but looking at the tach its not. Any ideas whats going on?

 

Sounds like a IAC [idle air controller] problem. Do a search on 'IAC', pages of info on the subject and a very common Ford problem.