Hi,

Lately the idle speed on my son's 1988 190E has been very erratic. It usually runs around 800 but for no reason sometimes goes as high as 2500 and gets stuck there. If the gas pedal is hit a couple of times it usually goes down to normal. Occasionally when hitting the gas pedal does not work he has to shut the car off and start it again. It happened with both a warm and cold engine.

I tried cleaning the linkage and lubricating but it still happened. Any suggestions would be greatly appreciated!



Thanks,

Bob Koziak
1988 190E 128K
1983 300D 116K
1990 300E 87K

 

try cleaning the idle speed solenoid valve.

 

Your problem sounds like a vacuum leak problem. Gasket leaking somewhere in the engine. Had the same problem with chevy 60 degree v6 engine. I fixed this problem by installing new plenum gaskets. Completely different than the 190e engine but this advice might help. Check the PCV valve make sure that gases are good. Check the intake manifold gaskets, if thay are leaking or are cracked it will cause the erratic idle that you are talking about. Hope this helps!