computer problems

have had this problem twice now and no one knows why but every one in a while when the car sits for a few days with out running it just runs like shit, really rich and the only thing i can find to fix it is to disconect the battery to reset the pcm then the car runs fine every day as long as i run it every day :confused: :confused: :confused: any advice would be great

Sounds like a bad O2 sensor to me. Did it set any codes?

no, no codes set at all