Can someone please tell me what should be the normal idle speed for a 4 cylinder 1994 C180 which has a 1799c motor? Mine is doing 1000rpm at starting cold and I always thought it should be lower like 750 to 800rpm only. This is without the aircon on at all. Usually with this on, the revs goes up. It was quieter and lower rpm before I got a techie to do some work on the vacuum system(leaks in the diaphrams) and look at the exhaust system which seems to be making unnecessary noises and may have some holes or leaks.

Tomorrow he will replace the whole exhaust system to get rid of the complaint and then look at whether the engine has developed some faults in the moving parts inside(pray there isn't any more problems or I will have to unload this car somewhere!!!