Skip the auto shop - Our mechanics make house calls

Q: Mercedes Benz 1997 E230 stumbling engine

asked by on

I own a second-hand Mercedes Benz 1997 E230 WD210.

Occasionally, while driving, the car has had some rough stumbling i.e. choking when accelerating. This happens even at high speed, 80-100kph. Once, it even caused the car to turn off its engine when accelerating out of a traffic light.

I have noticed that the problem seems to arise when the fuel tank is more than 75% full.

In the past 18 months, I have had the fuel pump, fresh air intake and camshaft sensor replaced. It seems that the problem has improved, but not disappeared entirely, causing me some anxiety when driving it over long distances.

What should be the problem?

My car has 18000 miles.
My car has an automatic transmission.

A: The information given states two different ...

The information given states two different vehicles. I will be addressing the first (E230). Its possible with the age of the vehicle that you hare having several issues. You are correct to address sensors, air, and fuel. All of them can cause issues like these.

Lets start with fuel. When you had the fuel pump changed, did you also replace the fuel filter? This should have been done at the same time. The fuel injectors can also be dirty and may need to be cleaned.

If you have not run the vehicle for codes, you will want to do that almost immediately. That way if the computer is picking up on something going wrong, you can start there with your diagnosis.

Oxygen sensors can fail as well causing drivability issues. Again, most of these sensors will trip a code in the computer. However some will not, or some may not be testing bad enough at this point to sound an alarm.

Start with trying to maintain some of the important fuel system components and test everything related to it as you proceed. Start with the simple fixes, and work your way to the more complicated systems. If you would like to have an expert pinpoint the issue in person, a qualified professional from YourMechanic can come to your car's location to diagnose the hesitation issue so that this gets repaired correctly.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: RPM's are higher than normal on gear changes

Hello. It may be possible that the computer is programmed to delay shifting when the vehicle is cold, in order to help warm up the vehicle faster. Once the vehicle warms up, however, shifting should return to normal. If the...

Q: Muffler might need replacement.

An exhaust leak can come from many places, including the muffler. A technician will be able to pinpoint your leak by putting a rag in the tailpipe, which will make the leak more pronounced and easy to find. I would...

Q: Fast idle - 1983 Mercedes Benz 380SL

Hello. There could be a problem with the throttle cable sticking, causing the high idle. There also could be a problem with the throttle position sensor malfunctioning, causing a high idle. Sometimes a dirty throttle body can cause this problem...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...