PeachParts Mercedes-Benz Forum - View Single Post

pawoSD · #3 07-21-2009, 02:02 PM

Do not use iridium spark plugs in that engine. Obtain the proper ones from your local Mercedes Dealer or from on Fastlane (this web site)....Roy can get you the right ones. They are a non-resistor "standard" plug.

As for the high idle, that would likely be caused by a significant vacuum leak somewhere. Where does the "economy" gauge sit while in park and while in drive? It should be in the black all the way to the left in park, and maybe a needle width or two to the right when in drive. It might also be a binding throttle cable, but that isn't very likely. Check all hoses and vacuum connections. Vac leaks = high idle on a gas engine.

As mentioned above, use the proper German paper air filter. K&N stuff is junk and let too many particles through, causing engine wear.

If it ends up that you can't figure out the issue I'd highly recommend going to a MB dealer, instead of an independent shop. The dealer has the knowledge and equipment/info to properly diagnose and repair the car.