my 350SD smokes a lot when under boost. it smokes really bad. has a factory rebuilt engine with only 20k on it. puts out a huge cloud and i can't see the cars behind me. but when they pass me i sure get a funny look. i have also followed the car a few times, and it smokes while just going around town. looks bluish, and i know it is hard to tell by sight and by smell, but i swear i smell some burned oil. the EGR system has been rebuilt. mileage has actually increased, and oil consumption is 1000-1500 miles/quart. i am pretty sure that is what it is, but of course Mercedes says that is fine. they say 900 miles/quart is unacceptable and my dad has never had any other mercedes diesel use oil. so we both think that any oil consumption is unacceptable. the car also has a lot of diesel knock, and it misses bad too. start it up and it misses for a good minute. that could be glow plugs. it has been into the dealer repeatedly to no avail. although they have done a lot of warranty work. besides the rebuild of the EGR system, it has had 3 or 4 sets of new injectors, a new injection pump, new chain tensioner, and the injection pump was also timed. this is a hassle. any help with this would be appreciated.