My idle drives pretty much good in all gears except when in reverse it drives about 300 rpms lower? My idles is set at around 1100 but don't know why? Also when driving I push the gas pedal slowly but sometimes it idles and speeds up high,and when I try to go full speed the car wont go pass 70-80 mph? I tried cleaning the idle air control valve,throttle body, and fast idle valve but it only fixed the surging problem that I once had. Does anyone know what system or component this could be?