high idle all the time

Hi, I have a 2002 nissan gentra gxe automatic 1.8l. All of a sudden everyday now the car runs terrible. I start the car cold and it idles at 1500 rpm even and never drops from there. When we drive the car it barely moves and it also stalls sometimes. I looked all over at any vacum hose thats maybe cut or anything unusual. New spark plugs also but that was after the problem. Any suggestions at all. Thanks please help