Mysterious Problem Baffles My Mechanic
I have a 1995 S500 2Dr Coupe with 44K miles. If I do not drive the car for approx. 1 week, it starts right up and runs fine BUT 15 minutes later the engine starts to idle rough
and eventually stalls. If I try to immediately restart the car the starter kicks in fine BUT the car engine will not turn over and it BACK FIRES with a putrid sulpher cloud. If I wait approx. 30 minutes after it stalls it will start right up an runs perfectly as if nothing ever happened. If I drive the car daily, or every other day, it runs perfectly. The problem ONLY occurs when I let the car sit for 1 week. It is VERY predictable and occurs like clock work. My mechanic thinks its a bad sensor. He hooked up test box to computer port in engine while it was idling rough and it showed NO problems. He changed the thermostat sensor but that did not help. HELP !!