I own a 2002 HO 6sp with AFE air filter, 4in exhaust, and no muffler. Plus an Edge EZ box. When traveling down the interstate at 60-65 mph, the engine will surge appox. 200-300 rpm. Recently, it has been getting worse. The Edge EZ box has been unplugged. But, the problem still exists. It also has been idling bad. Any ideas what might be the problem???? 
