Engine dies.

1996 Chevy Silverado, Z71, 4WD, 121000 miles, no noises/fluid leaks, automatic. Recently bought from my son. Check Engine light came on. Code indicated Crankcase or Camshaft Position Indicator. Put in shop, had distributor, distributor cap, rotor replaced and fuel system flushed. Truck ran fine for around 1200 miles. ( I only use this truck to travel to/from work, ~ 25 miles round trip, less than 10 days per month as I carpool ). At times, engine just dies. I stop and restart w/o problem and it'll run fine. A couple of times, while restarting, engine was very sluggish but would stay stay running if I pumped accelerator until it got going. Otherwise, engine runs smooth. No indications of when engine will die or struggle to start. Most of time, it'll start like new. Anyone out there w/ similar experience or advice?