I am looking for a bit of help with a mystifying problem. My 1990 300TE with an M103 engine has a problem in its warm up stage. When dead cold, it starts perfectly and then runs OK for the first 3 to 5 minutes. If it then has to say stop at a set of traffic lights and go to idle speed, it goes to idle speed (about 700-800 rpm) and will then drop onto what feels like 4 cylinders. To get it away again requires easing it off with virtually no throttle and it runs fine until it has to idle again when it does the same-goes onto 4 cylinders(If it has to be parked in these first 5 to 10 minutes it is extremely difficult to restart). It continues to do this up until it has been running for about 15 minutes when it idles perfectly and runs like this for the rest of the day, stopping, starting, and running OK. Leave it to cool down overnight and it will give a repeat performance when next started. So far have checked distributor cap, plugs, plug leads, compressions (all OK), wiring,earths, and replaced the cold start valve. Next step is the temperature sensor followed by the crank sensor but not really confident that either will be the problem. Has anyone had experience with these symptoms and has anyone got the cure?
Linear Mode
