I have 91 f-350. Just put a new trans in. It was shifting hard and the check engine light came on. Took it in and the codes said my map sensor was bad. They put a new map sensor in and the truck ran great and shifted nice. Three days later the check engine light came back on and the trans was shifting hard again. Took it back in and the map sensor was bad again. Does anyone know what would cause the map sensor to go out so fast. I pick the truck up today with another new map sensor in.