My wife and I have an '82 240 Dl and have begun to experience pretty severe CO (carbon monoxide) poisoning symptoms while driving the car (e.g., difficulty breathing, light-headedness, headaches, etc). There is a pretty distinctive exhaust smell during the onset of the symptoms, which are the most extreme in hot weather, particularly when driving up hills or accelerating from stop signs. The problem is not ambient traffic fumes, because we have experienced these symptoms w/o traffic. We took the car to a smog/muffler shop, and they noticed a small leak between the exhaust pipe and the entrance to the muffler (not the muffler to the tail pipe) but claimed that such a leak would not likely contribute to CO entering the car. They noticed that the seals around the trunk were poor but doubted that could be a problem. They tested for CO and hydrocarbons in the car, but I'm not sure that the test replicated driving conditions, since the car was up on a lift during the test. Has anyone had exhaust problems like this with a 240? Any thoughts/suggestions?

Best,
Paul McBride