[chandlerbenz]

I'm no Mercedes expert... I'm still 10 days away from even being an owner... but I know a thing or two about ECUs. I used to work for Cummins Engine Company as an electrical engineer, in the design/development of ECUs and associated electronics (sensors, wiring, etc).

Anyway, the point I want to make is that you should remember than when you replace the ECU, you are ALSO replacing the software that is loaded into that ECU. Before replacing your ECU and spending huge bucks, you might want to check with the dealer to see if a software update (a "new calibration", we used to call it) is available. It's always possible that part of your problem lies in the software, not the hardware.

You would be astounded at the number of things that are adjustable in your ECU's software. At least, that's the case with Cummins engines 1998-present, and I'm sure it applies to other makes/models/years of engines as well.

Just food for thought from a newbie here.

One final comment on ECUs. You know the ECU that is in 1998/1999 Dodge Ram trucks equipped with Cummins engines? Those cost Cummins $211 each to buy from the manufacturer (Motorola); yet, like every other ECU I've seen, the end customers (you and I) pay upwards of $1000 for replacements. Astounding margins on some of this stuff.