1984 MB 380SL, 1988 MB 560SL, 1983 MB 300CD, 1984 MB 300SD, 1985 MB 300
Lately, I have a really bad idle when I start my 83 300D (242,000 miles). The car idles badly when I first start it (rocking back/forward). After about 2 minutes, it smooths somewhat but not like it should. I have checked all glow plugs & they are fine. I have changed both filters. I have replaced the primer pump (thinking I was getting air in the system). I also have used the new primer pump before starting the engine to get out any air in the system (but no improvement). I ran a quart of transmission fluid with a tank of diesel (but no improvement). Lastly, I replaced the rack bolt on the injection pump. Any help appreciated. I am out of ideas! I am thinking I have a bad injector? If so, is there a way they can be tested while in the car?