It starts off with the “birth” of a young car. In his teenage years or so, Junior gets into the fancy gas. Mom exclaims something like “George! He’s filling up with ethyl!”
The now excessively peppy Junior zooms off and eventually gets in a wreck with a train. The “surgery” to repair him has dialog like “Spark plug… Fan belt”
Everyone I’ve described this to either has no idea that “Ethyl” used to refer to premium gas with lead, or they remember the cartoon but can’t identify it. Because of the leaded gas reference, it’s got to be from the early 1970s or before.