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Q: Sudden loss of power on 1993 Mercedes-Benz 600SEL

I have a 1993 600SEL with 55,250 original miles. The other day after driving about 100 miles round trip, while driving for some time at approx. 35 MPH the engine lost power.

I could 'floor it' and yet the engine barely had any power and very slowly crept up on RPM and then at 4,000 RPM changed gears. The car would come up to about 45 MPH but it was a struggle.

WHen at a stop light I put it in neutral/park and tried to rev the engine. It would only go to about 2,500 rpm and running very rough.

Almost like there was lack of gas or air coming to the engine.

Any ideas what may be causing this? HELP!
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You really need to Diagnose this issue. Any Check Engine Lights coming on? If so, there is 1 or more codes that will help you. here is an article on the Check Engine Light:

I would take your car to a good German garage. This car is very sophisticated and needs a skilled tech to deal with it.
please make sure use correct range octanage gasoline poor quality gasolina causing lost power
Have you analyzed the o2 and mass air flow sensors? My 93' 600sel has the same problem and when analyzed by the dealer I was told it was more than likely the mass air flow sensor, or O2 sensors, or throttle motors. I replaced the O2 sensors first with little success. Then I replaced the mass air flow sensor on the passenger side which helped a great deal but not entirely. When the budget allows I'm replacing the drivers side mass air flow sensor. I hope that does it, because the dealer price on the throttle motors is about $7,000. If they need replacing.....the car will become a parts vehicle. When the car balks like you describe, turn off the cruise-put it in neutral, and restart it. It should run correctly for a while to get you out of trouble on the road. Happened to me during rush hour on the I-system in downtown St. Louis......scary!
Hey I would like to buy that car if you still have it...please let me know if you interested in selling it.
Test your electronic throttle control module. Beckmann Technologies rebuilds the units.
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