77 pickup, stock setup, starting shutting off while driving. Normal routine is for me to start/warm up for about 5-6 minutes. Truck runs and idles fine for about 10-12 minutes, than start feeling some misfires, hesitation, start loosing power, ultimately resulting in engine shutoff. I had replaced all the vacuum lines about a month ago, and truck had been running fine. I rechecked to make sure all of them were firmly connected, and are good. Went ahead and replaced ignition coil, rotor, spark plugs, and cables and still have this problem. any insight on were to look next would be a great help. Thanks in advance JC.