The tiny but terrible crack

For some months now, i found that my car has been performing in a strange way. Imagine this... vrooooooocoughcoughooooommmmm. Earlier this week, i had my car's oil changed and the engine area washed. The guy at caltex was quick enough to see that there was something wrong with my distributor cap. There was a spark escaping every now and then. It came from a hairline crack in the plastic that you cant even see unless the car was running and you follow the path of the spark. It was about a half centimeter long and very very narrow. That little crack was the cause of the engine's entire malfunction. All it took was a little electrical tape and my engine's cough was gone. Crazy no?