Jeep idles around 680, with scaner attached I can make it idle at the correct RPM's disconect IAC no change. Engine has misfire code, attach scaner, scaner show's which cylinder is misfiring, change coil pack and misfire moves to another cylinder. Checked for vacume leaks none. Changed all spark pluges with required plug, replaced all coil packs. Replace crank sencer. Is this my ECM.