Not to refute or ignore the advice of experts, but although the items you described would probably need replacing considering the age and mileage on your vehicle, NONE of those issues contribute to misfiring!!!

In fact, your car would still run and drive normally, although the oil leaks and overheating issues would be a problem.

1. Is your car overheating, and are you seeing oil in the coolant reservoir or prolific oil leaks around the head? If you can say NO to all of these, I'm not sure why that diagnosis was made?

2. MB water pumps tend to fail dramatically...one day all is well, the next, a Valdez-sized coolant spill resides underneath the car! If this hasn't occurred, then you don't have a water pump problem either.

3. Collapsed or worn engine mounts would contribute to vibration..usually noticeable at idle but sometimes misinterpreted as suspension vibration at highway speeds.

Although I have a different engine than yours, I had the above items replaced at one time or another, and none of them were replaced under the guise of a misfiring issue. The $1500 quote for the gasket is pretty decent, but add the cost of the other items, and that's a big chunk of change for reconditioning your engine compartment, only to have the misfire problem not get solved.

My two cents...for whatever its worth.


P.S...has your engine harness ever been replaced?

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car