The most rusted vehicle I've ever bought came out of PA, in 2000.
Oddly, it was the floor, nothing visible in the rockers or quarters.
I've never bought anything from another winter-salt State, so I can't say what State is worst.
Come to think of it, I worked at a dealership body shop in North Philly back then, and the used car trade-ins were horrendous.
I just noticed the PA plates on the car. IDK where the car spent most of it's time , but the window sticker says selling dealership was in Philly?
Perhaps it has been a lifelong PA. car? The seller would have info on it I would think.
