I just bought a 95 C280, with about 140K on the motor. At times it will run very ruff, like it's out of time or something. But I've noticed that if I turn the motor off for a few seconds and restart it, it will run normal.
It dosn't run ruff all the time but it seems to be happening more and more frequently.
Any idea as to what would cause this

The engine control module in your car constantly monitors engine performance, so if any cylinder has a misfire due to bad sparkplugs, defective coil or any other reason, the engine control module will shut that cylinder down via injector cut, turn eng off and back on will reset eng control module.

The main reason for this is to protect the cat from raw fuel entering and causing a melt down.

First thing I would suggest is doing a basic tune up, replace spark plugs, inspect coil ends and plug boots for any sign of moisture or arcing, air filter and fuel filter if you are confident in doing so.

Failing that I would suggest having it scanned for fault codes, this will lead you in the direction of your problem.

Then you could post results and we could try to advise with more specific information.

ozzy.

Replace the coil to plug connectors. There are three of them.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Wonder if this is what going on with my E420?? The car will run like a clock for days on end and out of the blue will run like crap! But it to is starting to happen more often. I have not tried to turn off the car and restart to see if it clears. Afraid it might not start back up again!!


Smokie

As it clears right up with restart, I would check the OVP relay first.

When conditon develops, tap the relay a few and see what happens.
Archieves - "OVP relay.." There was a part change/upgrade on that item.

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1D00YU6RY1JV0NGYI0&year=1995&make=MB&model=C-280-001&category=P&part=Overload+Relay

..and change the coil connectors mentioned = even if it is the relay.
As you just bought the car , the 3 common problems on that chassis are coil to plug connectors, OVP, and wire harness..
First two are low $$$.
Any/all can cause your complaint.

Just wondering. The coils are about $75 per? Is that considered low $$$? Wanted to make sure I was checking out the right part. Thanks.

Had same problem on my 96' c280.There are boots under the three coil packs as well as on the three wires going to the spark plugs.Theses simply unscrew from the wires.Change all six,with new plugs.I reset the computer by removing the neg. terminal on the battery for ten seconds or so.The car ran rough for a minute until the computer adjusted,then all butter.