Cool things with wheels since 2006
The static suppressors did.
Yes, I remember in the 80s a lot of cars that had engine interference in the radio. Sometimes it was funny.
The static suppressors would help on engines that had non-resistor spark plugs. Using resistor core ignition wires would probably do the same.The spark plug intensifiers probably had air gaps inside them. The spark energy would have to build up enough to jump the air gap in the intensifier, then fire the spark plug gap with the same energy. These would make the radio static worse because of the extra sparking that occurred for each cylinder.