Hey guys I am needing some help diagnosing my 2006 MCS. I got it used about four months ago and I have always had a mysterious electrical issue. The car runs and drives perfectly at lower RPMs but anytime I rev it over 4.5-5k the radio, navigation screen, and gauges shut off. I also lose the electric power steering and the dash board acts as if the car has been shut off. The engine will operate normally and I can continue to driver normally but without anything working on the dashboard. Once the revs fall below 4.5k everything comes back on and acts fine. This issue happens in any gear and even in neutral at a stand still. No codes are saved in the computer and no CEL on the dash. I am lost as to what could cause this. Any help is greatly appreciated. Thanks.

I suspected that to be the case as the alternator just failed last week. I installed a new one and have check the voltage. It is not over charging but the problem still persists.