85 190e Rough Idle

UPDATE: 8/15/03....Checked the compression on all cylinders yesterday, found that the #4 was only 65 psi, other three were about 160 psi. That would definitely cause the rough idle. Now I have to decide whether or not to just do a valve job (engine does not smoke or burn oil), or go deeper and overhaul engine ($$$$). So, am continuing to drive it for now, as the idle is the only bad part of the car. :repost:

My 1985 190E slowly developed a rough idle. Was hard to start over the winter, especially the cold days, but starts better, almost normally now that the weather is warm. After starting, the car seems to idle normally for a couple of seconds, then kind of "drifts" into a rough idle. If the throttle is increased just a little bit, the engine smooths out and runs fine. It also runs fine at highway speeds, and the gas mileage is about the same as it was when it was idling smoothly. Have replaced the plugs, distributor cap and rotor. Took the new distributor cap off last night, and there is one of the contacts that has a light film of gray buildup, the others look like new. Any thoughts?

i had similar problems with my 87 300e.

i took it into the shop and the guy said "i have no idea how you got it here"

so the basically reuilt the tophalf of the engine and it was like a new car. i would suggest doing it (if you can afford it, it is expensive) cause itll cause more damage in the long run.

I had these exact symptoms, my mechanic replaced the overload relay and the car runs great again....'Hope this helps some1 in the future...Phil