PopScis of old apparently enjoyed teaching the reader about the inner workings of automobiles through humorous, Encyclopedia Brown-esque anecdotes. In this tale, our hero, Gus, who prefers staying in and tackling tough engine jobs to going out fishing with the boys, has a run-in with a couple of hooligans from the neighborhood. If he's such a good mechanic, they taunt him, maybe he can figure out what's wrong with their car.
Some green whippersnapper mechanic from a startup garage tries to help find the problem with some newfangled technology, but our hero doesn't need all that. He quickly determines that the hooligans are pranking him for April Fools' Day. They've switched two of the spark plug wires--"the oldest automotive practical joke in the book," Gus says, and charges them eight whole dollars to teach them a lesson.
Read the full story in Gus Challenges an Electronic Marvel