Okay usually our mechanic can figure out what is wrong and fix it the 1st time. Problems started about a month ago with a whiny turbo, an apparent oil leak (oil coating the block), then about a week later there was loss of power, tons of smoke, rough idling, lunging (van would lunge forward at random moments), and the van would also not downshift when the incline decreased (you would either have to let off the gas to make it downshift or use the gear select feature). So my dad took it in to have an oil change and the fuel filters replaced (his idea of what was wrong) and also it has to be taken to the Mercedes dealership to have major work done for a recall (a manifold was replaced along with the wiring harness and some sensors and some other things). So he takes it out of the shop and at first it feels normal then there are the same problems so he takes it back to our mechanic and the mechanic figures something may have not been reattached right (a bolt was one thing, as soon as that was taken care of the whine of the turbo was gone, and a pipe was another thing). So my dad gets it back, feels normal once again and 3 days later he is having the same problems so he took it in today and out mechanic believe there could be oil up in the turbo or that the turbo might need to be replaced (van has 133K miles on it), also that there might be a fault in the ECU. Have you guys taken your Mercedes in to your mechanic and it come back seemingly fine then you encounter the same problems again?