Last week I had a customer with a 1998 C230, complaining what they though was a transmission relayed drivability problem, lack of power, bucking and erratic shifting. The car had two codes, P0300 random misfire and code P0170 fuel trim bank 1 malfunction, the adaptation value was at the max. Road testing the car, it felt like a load input problem, the Fuel pressure was right. I change the MAF sensor, problem solved. Get a second opinion.