two days ago when i went to leave the hardware store my truck would not start. It would roll over strong as it always does but it seemed like it wasn't getting any spark/fuel to get it running. I opened the hood and jiggled some wiring around and tried once more, and like the flick of a switch it just started without hesitation. It definitly seemed like there was a loose connection somewhere but i drove home hoping it wouldn't occur again.... Well this morning it happened again, but this time it just wont fire, no matter how much i jiggle the wires . I took out a spark plug and i tested it for spark and it appears that it isnt getting any spark while the engine is rolling over. im very scared of electrical problems and am kinda new to owning a vehicle so i was wondering if there was a common problem with the distributor or some wiring that comes loose sometimes that's not easy to see? The engine runs smooth and never ran rough after it started at the hardware store, which i think means that the coil/spark plugs are still good.