Long time lurker, first time poster.

After searching through the archives for the past couple of days, I haven't 100% 'virtually trouble shot' my issue.

Here's my issue. 1992 300CE w/131K.

The car runs great at first start up...no issues. However, once at normal operating temperatures, at idle I get a very small 'miss' which takes the rpms from 800ish to 500ish for less than a second. This will happen every couple of minutes, not continuously.

Again, at normal operating temperature and once the 'miss' has surfaced, the car will hesitate slightly during acceleration from a stop.

The biggest issue is, once again at operating temperature, I can be cruising along the highway, at speed and the car dies, driving around town it'll die, slowing to a stop, it'll die...no warning, no bucking, no warning lights...nothing. The only thing that happens is the tach drops from whatever RPM it was at to zero. It's almost as if someone turned a light switch off.

Only when I stop to restart (shifting into neutral doesn't allow me to start) do the dash lights come on (as if you had turned the ignition on without actually starting the car).

Recently, it struggles to restart once it dies, and takes a few cranks to get it to fire.

This problem has become more and more severe, to the point where the car will stall 5 times on a 3 mile trip.

The OVP was changed out a couple of weeks ago, as well as new plugs, and fuel filter. Fuel pumps cycle per normal....

...HELP!

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Jerry St. Germaine

'92 300CE
'04 E500
'74 Porsche 911~the only thing from '74 left on it is the VIN

Jerry, when was the O2 sensor last changed? Replacing the O2 sensor on our 1991 300CE eliminated the hesitation from a stop. If you do a "search" under O2 sensor there should be various posts advising how to check that the O2 sensor is functioning properly.

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Fred Hoelzle

My stalling problem was cured after I cleaned the ICV.
Do a search on ICV.

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300CE 1989 Euro Model.
ML350 2011.

OF course there are many possibilities for that stalling problem.

Have you OR have you had the ignition system checked? DIST cap, rotor, spark plug wires, coil??

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MERCEDES Benz Master Guild Technician (6 TIMES)
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190E 2.3 16V ITS SCCA race car (sold)
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Retired Moderator

Thanks for the responses both here and via PM.

Ferdman - We've owned the car for about 30K (two years) and I have never replaced the O2 sensor.

kk9 & M.B. Doc - I'm going to go through these today to see if I can find anything faulty. With my conditions, I am pretty sure I can rule out fuel supply...shouldn't a fuel problem give you some warning like a sputtering as it runs out of fuel to the engine?

I'll report back today with what I find.

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Jerry St. Germaine

'92 300CE
'04 E500
'74 Porsche 911~the only thing from '74 left on it is the VIN

I think I may have found the problem...I pulled the distributor cap this morning...I'll let the pictures speak for themselves.

Yes...the debris you see at the bottom is from the cap...

...new cap, rotor, wires, etc ordered and should be here tomorrow AM. I'm hoping to be back driving it this weekend.

Attached Thumbnails

     

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Jerry St. Germaine

'92 300CE
'04 E500
'74 Porsche 911~the only thing from '74 left on it is the VIN

Jerry, I'm curious to hear if the new distributor cap, rotor and ignition wires solve all your problems. They should definitely make a noticable improvement.

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Fred Hoelzle

I'll definitely post back once the new ignition parts are in...I'm crossing my fingers that this will be THE cure...however, Mr. Murphy and his laws have always made my days memorable!

__________________
Jerry St. Germaine

'92 300CE
'04 E500
'74 Porsche 911~the only thing from '74 left on it is the VIN

Jerry, hopefully your new sparkplugs are Bosch F8DC4 and not a platinum plug.

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Fred Hoelzle

Hey Fred!

The new plugs are the Bosch units and not any fancy-schmancy platinum jobbie.

I installed the new coil, cap, rotor, and wires today. Took off for a 'bring it to normal operating temperature range' drive. I could be a victim of the placebo effect but it definitely seems to accelerate a bit crisper, no hesitation.

Pulled into a parking lot and let it idle for a couple of minutes...no slight miss as before.

I drove around for a good half hour, fully prepared to have Mr. Murphy rear his ugly head...nothing. No stalling, no slight miss...

...so far that is...I'll put some miles on her this weekend and report back again. I'm stillcrossing my fingers.

__________________
Jerry St. Germaine

'92 300CE
'04 E500
'74 Porsche 911~the only thing from '74 left on it is the VIN