Silverado 4.3 turns over but seems to have no spark

boppascott

My 2002 Silverado had been starting o.k. but when I would take off the headlights would go dim . I had the new battery tested then 2 weeks later it died while warming up and later that day I starting to drive it to move it for calendar parking and it died.The radio went to a station like it lost all power now it turns over great but no spark.any thoughts ?Also now and the it would hiccup while driving over the last couple of years