Can any body tell me what the symptoms of a bad wiring harness are? I ask because I have a '96 c280 with 86k miles that exhibits the following symptom:

1. When accelerator is applied from a dead stop a popping sound is emitted than car suddenly idles rough as is some of the spark plugs have stopped firing.

2. To reset the problem I have to switch off and restart the car and every thing's fine. At this point the car is drivable, but I simply can't accelerate suddenly, it has to be done slowly and gradually to pick up speed.

I suspect either a faulty wiring harness or a vacuum leak. Can anybody help????