Well, believe it or not, just 1 fouled plug. I have a 97 e320 with roughly 115,000 miles. I have been changing my spark plugs quite often lately. All of the plugs look ok, except for the plug on cylinder #5. My check engine light is on, and im quite sure it is due to this. I have done, or done by mercedes mechanics, the following repairs over the last 6 months:

New Plugs (as mentioned, often)
New spark plug wires and new coils
new mass air flow sensor (performed by rip-off dealer, cost $1,000)
new fuel filter

Also, I get terrible gas mileage when I drive around town. On the highway, the gas mileage is pretty good - it appears to be what I should be getting, based on other threads I have read. When I start the car first thing in the morning, the idle is rough. It's almost as if the car is breathing 'hard'. If I put the transmission in reverse before it has had ample time to warm up, and hold the brake pedal down, the engine lurches....it's like I was choking a person, and he would be frantically trying to get oxygen.

Any ideas on what the problem is? Maybe bad fuel injectors? Or, could it be a crankshaft position sensor? Oxygen sensor? Thanks in advance for any input all