My friend has a 1990 300SE (M103)with 172K. Runs perfect, but the car has a funny issue that my 300SEL actually has from time to time.

*When going steady, say at 40 mph, on steady acceleration the cars engine power will fluctuate, as if she is working the pedal. Even on moderate acceleration it will do it. I have driven it and felt it and actually mine will SOMETIMES do this. Not at any certain speed, but pretty much at any speed hers will do this on steady acceleration. its like it gets too much gas, then too little, too much, too little, etc.

She said hers has been getting worse over the past few weeks. It also has a slight splutter at idle, so I am guessing it may be related?

Does anyone have any ideas what this is and whats the fix? I was once told it was possibly the airflow sensor potentiometer, then someone said plugs, then someone said something about there is something under the air cleaner on the back of the throttle body that needs adjusting?

Not sure about her car, but I know that mine will always start very easily, hot or cold... however I do have a CEL that will come on 15 seconds after its first started then on for only about 45 seconds after that. Not sure if its related or not. Have not had the code read, as I dont know if a local auto parts store can check this car like they can others... where is the hookup for the computer on these cars?

Any help appreciated.