Fouling spark plugs
 

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

<<New Plugs (as mentioned, often)
>>

What's in there now??

The last set of plugs I used were Champion RC12YC. They are copper. I have used Bosch 4 tipped before. They are a waste of money (lol).

Here is some more information that I remembered since posting the original thread. At one time, it was just the #3 cylinder that was fouling the plug. I do believe that the plugs are gas-fouling, as the engine does not burn oil at all. There is no smoke coming from the exhaust that I can tell. I purchased one new fuel injector, but did not install it myself. When I had the MAF installed at the rip-off dealer, I think he changed the fuel injector. However, I cant say that with 100% certainty.

Those are Resistor plugs .

The car takes Bosch F8DC4 , non resitor plugs . no other.

I would change them to the F8DC4 and change the resistor/connectors under each coil.
Then Scan/Clear the codes and give it a try.
Write down the codes.\ that have triggered CE..

..and read this post, the last one in particular.

http://www.peachparts.com/shopforum/tech-help/69677-bosch-platinum-4-spark-plugs.html

Thanks Arthur. I'll give that a try and let ya know how things are.