On my way to work this morning and as I was coming off a major highway off ramp to enter another highway truck started to buck a few times then once I was starting to accelerate on to the new highway the engine died and wont restart. Had it towed home. I was thinking it maybe the cam positions sensor , but I noticed that when I turn the key on the Wait to Start light does not come on at all. Which is a first. I did change the cam position sensor , but that was not the problem. I read that the WAIT TO START LIGHT is fed from the PCM , could the PCM be bad ,? how do I check it . I noticed that The truck would buck on occasion over the month or so. But other then that the truck runs great with 217,000 mi. on it. Also I did change the glow plugs , glow plug solenoid, and new valve cover harness as well back in September.