I agree with that wholeheartedly. If a neighbor’s car is illegally transmitting on frequencies it’s not licensed for, and the neighbor’s the rare sort of jerk I would be afraid to talk to about it, I wouldn’t have qualms about reporting it to the FCC along with timestamped logs of when and on what frequencies. It could be entertaining to see the feds slap an injunction on someone to prevent them from starting their car.
(NB: It’s way better to talk to your neighbors, obviously. I think we all know at least one knucklehead who wouldn’t respond to reason. I’d reserve this drastic measure for that sort of situation.)
These motors should not be causing the issue because if they block AM reception in that car, they’ll do it for all cars around them.