Mass Air Flow Sensor Problems of Mercedes Benz SL600

Engine wiring is failing , the injector wire harness failed and had to be replaced. The throttle actuators wiring failed and damaged the actuators and had to be replaced. The mass air flow sensors wiring failed and damaged the mass air flow sensors which had to be replaced but since the wiring in failing it is causing the vehicle to have a higher pollution out put. The body mounted engine wire harness is failing causing many failures with engine and fuel , exhaust , pollution controls , and other operating systems. The wiring insulation is crumbling throughout the engine bay wiring harnesses. The body mounted engine wiring harness which includes the mass flow sensors wiring is not available to purchase. Due to the crumbling wire shorting out and miss reading tests and shut down to limp mode. The car is unsafe and unusable. Over the past 5 years the only miles on the car have been back and forth to the shop for repairs. Other then about 100 miles which has been the drive after repairs when the wiring problem causes another problem which makes the car un-drivable. Since it the wiring for the entire engine and all the controls is crumbling and exposing bare wires , it happens while it sits , when it moves , when it stops or when it goes. So it can happen even while not being driven as well as while it is being driven. This has been a ongoing problem since I have owned the vehicle 05/29/2007 and it is waiting to go back to the shop now for the wiring which we can even buy 03/21/2016.