Hi All! Over the past six months, we have had on and off problems with our ML 320 CDI with approx. 45.000 KM during 3/4 to full acceleration. The ML would start to go and then "studder" several times, until you let off the gas. Also, a few times while driving on the highway, it went into a sort of limp mode, where max speed was 80 or 100 kmH. We would pull over, turn off, restart and problem solved. Never a warning light. Of course, this is not only a convenience issue, but also a safety one, since you never know if it is safe to overtake or not.
I finally found time last week to take it to the dealer. According to the service manager, they ran a diagnostic and the comp listed "clean or change air filters". Indeed they opened them up and they were totally dirty and clogged. They cleaned them, but decided it better and safer with new filters. (2)
In total I paid about EUR 200 ($250) for the diagnotic check and the parts and labour of the change. Now I have just came back from an hour test drive, and it is such a good feeling to be able to get full acceleration again, without the constant herky-jerky. Not only is the acceleration smoother, but also it seems more powerful. It makes sense, that if the air filters are very clogged, the performance cannot be at its maximum.
At the last service, I think C or D, I took the ML to a local Bosch service shop instead of MB to save money. I had a feeling then, it would be a good time to change the air filters, and thought that would be part of the service. according to the shop, air filter change was not listed, and therefore not performed. That was 5000 km ago, and would have saved me a lot of trouble. Now my board comp shows a Service E in 15000 km. That would be at about 60.000 KM and about 3 1/2 years, perhaps a good time for a full MB Services. (Tranny fluid, brake fluid, filters, etc.)