NestorLupo3l

Hello, have a problem with the 3l automatic transmission. when I'm driving, suddenly in the middle of driving, it shifts out of gear and loses the gas pedal. the engine just idles. and then I have to stop and turn off the engine, then when I start it again changes gears normally without any problems, but after a few kilometers the same thing happens again....does anyone know what it is about...no mechanic knows what it is about