Rough Idle & No power below 2500, C220
 

Hiya Fellas:

Yesterday I washed my engine compartment...nothing crazy just a low pressure (garden) hose and rags.
My car was running fine before the engine wash with the exception of an apparent kickdown switch failure that I was living with and dealing with by manual shifting - albeit that, the car was idling and running fine.

Well, after the engine compartment wash, now my car idles very rough, goes up in rpms very shaky when parked up to a violently shaky 4 - 4500 rpm (but I'm not sure if it always did that). When running, there is no appreciable power from idle to about 2500 when (at speed) the car seems to run ok. When idling it also sounds like a lawnmower, also when driving up from idle speed to about 2500. Once it gets to speed, it seems to be ok although it can't be nailed to test since it's got the bad kickdown. If I manually downshift, it picks up with some apparent power too - the car was never a hot rod.

Anyway, based on a couple of searches I went and crudely tested the OVP and ran it without it's fuse. The car ran the same with the exception of the ABS light being on. I don't know if I had to actually remove the OVP to test it's function (I didn't tonight).

So that's the scenario, the car ran fine with a dirty engine compartment and now it doesn't. The engine compartment is clean but I wish now that I hadn't cleaned it.

Please help with any suggestions.

Pete

The car is a 1994, C220 - sorry...Pete
 

didn't put that in the post

If you have access to compressed air in large quantities....Use a small nozel hand operated attachment tool to go about the engine area and blow dry every crevice, crack, cranny and electrical plug or boot. Carefully use the high pressure air to force out the water everywhere you can reach. Once things are throughly dry, your problem should be solved. BTW, I use compressed air and an old dry paint brush to clean my engine compartment. What little dirt remains can easily be wiped off with a damp rag. Be sure to wear eye protection if you go this route.