RPM jumps on '95 C280 - PeachParts Mercedes-Benz Forum

Conrad1867 · #1 08-28-2006, 12:20 PM

I drive a c280 w/ approximately 123k on it. Recently, whenever I take the car out and then either put it in neutral or into the park gear, the rpm's will by themselves move from about 5-600 to about 1500 rpms.

Moreso, I noticed that if I turn the car on and keep it in park, this problem will not a occur.

On a side note, I just recently checked up on my spark plugs (which is probably one of the most time consuming things I've done). Could the aforementioned problem be a result of a loose insertion of a spark plug? I do not hear any misfiring though.

Any input is highly appreciated,

Conrad Kania
August 28, 2006

david s poole · #2 08-28-2006, 06:30 PM

most likely the throttle body has dirt in it not alowing plate to close properly and this is an electronic accelerator.clean this out with carb cleaner and see if it helps [ps when you put it in gear the trans load is pulling the rpm back down]

Conrad1867 · #3 08-28-2006, 08:48 PM

thanks for the input, I'll check that out.

Conrad1867 · #4 08-28-2006, 08:52 PM

on a side note, how do I get one of the three spark plugs from underneath the coil packs?