I have a 1994 E320. Two weeks ago I had the radio ant. motor replaced and the front brake pads replaced. No problems for the last 600 miles. This morning before leaving the drive, the ASR light comes on and the car goes ino "limp mode". While the idle was irregular and the car was in "limp mode" the antena and radio starts coming on and off. Very bizzaire to the observer. Why would this happen?