Truck stalled and now only cranks, will not fire up?

Pulled out of the driveway, heading to work. Made it approx. 1 mile when truck began to bog down upon light gas pedal pressure. I let up, it felt as though it was returning to normal, so then I pressed again on the gas, it bogs down again and completely dies. While coasting to a stop, I attempted to restart using the clutch and popping it back to life. That was a no go. It is now parked and with countless attempts to revive it, all I get is cranking with no signs of life. Checked oil, no visible signs of water. Checked tail pipe, clean. Also remember looking through rearview for traffic, no recollection of black smoke or smog from a possible head gasket problem. Prior to this insta-death, I remember hearing intermittent sounds of metal on metal coming from what I can only assume to be the timing belt housing. Truck does has a slight gap on one of the motor mounts, therefore it did shake a little but nothing that couldn't be tolerated. Spits and sputtering sounds came from what seemed like underneath the truck rather than from the engine area. Truck would idle high upon starting and then slow to almost a stall while producing the sounds of 'potata-potata-potata' from underneath. I'm not completely new to this truck since I have had it for 6 years and done most of the minor maintenance on it. However, she is dead and I am at my wits end on what the cause could be. If anyone could help, please do.