My 2004 CTS wont turn over. When I try to start it the starter cranks for a long period by itself. I've took apart the MAF and cleaned it. A dianostics thing was hookrd to it and it said some of the spark plugs was misfiring. I figured maybe the injecters were dirty, so I put some Tech-Ron adjective in th gas tank. Has any one had a problem or can anyone help?