Mercedes 1991- regular gas caused engine to sputter and stop

Power/Fuel
1

An attendent filled the car with Regular (cheapest gas) It drove Ok until it ran out of the good stuff, in about 20 miles.



It has 180,000 mile and no major repairs.



Then it sputtered and would not start. Finally with much ado it did start.





Anyone know what to do?

2 
I doubt if it was the "regular" gas.  It may have been bad gas due to gunk or water from the bottom of the tank etc.  

I would start by contacting the station to see if they had any other problems reported. 

Next I would replace the fuel filter if it has not been replaced in a while.  

Also consider it may have nothing to do with the fuel and maybe it is some other problem like plugs or wires etc.  

20 miles is a long time if it was the fuel.
3

If it’s running now, keep filling it with the correct gasoline and it should be fine.

I think there may be a problem other than the gasoline, because the car should still run even with regular gas.

4

When you fill a car with gas, the new mixes with the old (it doesn’t stay separate). So there’s no way your car could run on “the good stuff” for 20 miles and then start to encounter the bad stuff–something else is happening such as a bad fuel filter or dirty fuel injectors.

I have a 1992 Mercedes and on a few occasions throughout the past 12 years I have run regular gas in it–nothing bad happened but I didn’t make it a habit. Same goes for my 1984 mercedes which I’ve owned for 14 years.

A downside to using regular in a car that requires premium (such as yours) is that the computer may cause the engine to detune slightly to handle the lower octane which will hurt your gas mileage as well as horsepower. An engine knock sensor should stop pinging and knocking from occurring. I really noticed a performance difference in my 1984. I wouldn’t run regular on a prolonged basis, though–if premium is required then use it. There is a risk of engine damage after prolonged use.

I doubt that one time use of regular gas itself is to blame for your car’s symptoms. As soon as your tank is 3/4 or 1/2 full you can fill it up with premium and at least have your car running on the equivalent of mid-grade. And a fuel injector cleaner may be in order–add this to your gas tank.

5

Thanks so much for your timely and helpful information.

Good luck with yo ur car.

Anita

6

Thanks for your info. Sounds right I am on my way to start it now?

7

Thanks again to you all.

8

Umm. his tag line says gas Mercedes 350.
In 1991 the 350 engine was a diesel, as in 350SDL.
That might be part of the problem with regular gasoline in the tank.

How about it Digani, as it a gas or diesel engine?

9

It is Gas’ I know I saw that on the Internet but it id a Gas Engine and the Manual states it is a gas engine.

Thanks for your help. FYI I did start it today and drove a bit but I would not take it out of the immediate neighborhood as it is still not feeling right.

I appreciate everyone’s help.

Anita