Hi guys,

I made a thread over at the mercedesshop forum and it got to 4 pages long and now there is almost no responses so I decided to try here.

I will sum up the problem and everything we have done so you don't have to go through the entire thread.

Firstly, the car is a 1988 300TE with 65k miles on it when I bought it ($3000!) and it would stall randomly and misfire hard. Here are pictures of the spark plugs every 300-400 miles:



First we did a compression test and these were the results:
We next put 20/50 oil into the engine and it leaked less. (it was using a quart of oil every 500 miles)

Next we changed the duty cycle to 45-50% and replaced the OVP which fixed the stalling problem.

Then we replaced the Voltage Regulator.

Finally got round to doing the Valve Stem Seals at 72,000 on the car:




^ As you can see the engine is in amazing condition.

This solved the oil leaks onto the spark plugs and now it does not use a drop of oil at all through the 3000 miles before I get an oil change.

Next we replaced the Ignition Leads as they were certainly making less than stellar spark's with new Bosch leads which helped the misfire A LOT! It is STILL there though.

Lastly, we replaced the resistor style spark plugs with new Bosch NON-Resistor spark plugs like the car is supposed to have. I couldn't notice a difference in the misfires.


What is our next course of action to fix this horrible never ending problem?

The previous owners said they replaced the O2 sensor 6 months before we bought the car, but could it have gotten contaminated through the oil leaks we had?

What else could be the problem here?

Any help would be very appreciated!!!

Thanks, ps2cho