general problems of the 2008 Chevrolet Suburban

Last year 2012, the Suburban was blowing smoke out tailpipe, less than 100k miles, so dealership installed new valve cover with proper grommit for pcv under warranty. Sept. 2013 115k miles, engine bucking, dash lights all on, running on 7 cylinders, chevy dealership states #1 spark plug "came out". And that oil pressure sensor was bad, but still pressure, so not urgent. . . . Nov 19, 2013 - truck now making 'back fire' noises and pressure sensor moving back and forth across 40. . . . Afraid will break down again. Also, have peeling chrome on inside door handles like prior complaint, that is cutting hands/fingers!.