i was driving to class this morning and i noticed my rpm's just start to drop so i pulled over as soon as i could. try to restart it but the engine wouldn't turn over. anyways i leave it parked there and call my mom to pick me up and i end up takin his truck to class for finals. so later my dad heads to check it out and it starts up and runs just fine, so he drives it back home. anyone got any ideas on what could be causing this to happen. it's happened a few times before where i notice my rpm's dropping but it never completely died on me while driving. any help is appreciated.

 

thinkin it could need a tune up??