1995 E-320. I'm not sure what's going on, but here are the symptoms. First off, I noticed a subtle whine, I traced this to the power steering pump and suspect the bearings are on their way out. Whether this is related to the following issue, I don't know, it just happens to be going on concurrently. perhaps there's friction on the bearings causing the following issue? don't know.

second, occassionally the engine RPMs surge up and down, not drastically, maybe 300 or so. Not really bucking but a gentle surging of the engine. this doesn't happen all the time. when surging the engine is still smooth, not choppy or rough. I suspected a vacuum leak, but cruise control and door locks work, pushing the brake doesn't seem to affect this, or be squishy or any different than normal. engine oil level was high, so I changed the oil which seemed to have helped a bit, but not totally. meaning it still happens, just not as often. there also seems to be a slight loss of power while this is happening. It's an intermittent issue, no issues yesterday or this morning, but the day before on the drive home it happened, but only for about five minutes. the engine light did come on, I haven't downloaded the data yet.

could this be a fuel delivery issue? O2 sensors? bad spark plugs? manifold leak? or perhaps the PS pump is causing this? I'm at a loss!

IF you send me your vin and email addy Ill send you out some documents by the end of tonight.

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

Pull the vac hose off the Feul Pressure regulator and check for any evidence of petro on that port or in the vac hose.

I have surging when feet is off the gas. surges for about 3 times and then cruises along as if the throttle micro switch is open which allows gas. I made sure the switch closes when pedal is free. yet its the same.

Some say its the trans on its way out. Also it could be a lazy ICV. I have replaced the Fuel pump relay and still the same. So you might want to check the ICV. One sympton that I am having is that after coasting for maybe 20 miles, off the free way and to the first traffic light, the idle would be about 600. feels like the car is dead. It will take about 2 second to react and raise the idle to a comfortable 750.... Could be a lazy ICV.

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1992 200E
M102
102.963
AKA Silver Old Grumpy
Always hope I can freeze someone with the aircon- Just change the compressor again, Subseal leaked with a psssssssss sound.
Its the NON-3 Pointed star items on my car that cost more to repair.$%^&%%*^&

I checked the code box, pressed the button once for 3 sec. and got code 2, then pressed it again and got code 3. pressed again and then nothing, so I assume these are the two issues; O2 sensor bad and lambda control inoperative. O2 sensor is easy enough but what is the lambda control??

Thanks!