Q: Car misfires and fumbles during acceleration but regains pace. - 2003 Mercedes Benz C230

asked by on September 03, 2016

My car seems to misfire and has trouble engaging when going uphill or accelerating when entering freeways. Last night it stalled on me for approximately 30 seconds but returned to normal afterwards. I'm not sure if I'm having issues with my spark plugs, fuel filter, or fuel pump. Any advice or insight you could offer would be greatly appreciated.

My car has 163000 miles.
My car has an automatic transmission.

Hi! The symptoms you describe sound like a misfire caused by ignition components. Running ok until a heavy load is put on the engine, then stumbling and misfiring is typical of an ignition-related misfire. Spark plugs, wires, or coils are the usual suspects, and would be accompanied by a Check Engine Light and misfire codes. A fuel pressure test would provide helpful diagnostic information to confirm adequate fuel supply. An experienced technician, like one from YourMechanic, using a scan tool would be able to look at data that provides clues on which way to proceed. From there, they will be able to diagnose the misfire condition and conduct proper repairs.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

The battery light is showing on the dashboard

This may be a sign of a weak battery, a failing voltage regulator or failing alternator. As you may know, the alternator is responsible for charging the battery while the engine runs by generating amperage and recharging the battery while...

Check engine light was on and now temperature gauge go hot ? i replace the thermostat but still go hot .help ?

It sounds like you may have a number of issues going on. Overheating can be caused by a number of things such as low coolant levels, a faulty thermostat, a clogged radiator or a failing coolant fan switch. As you...

Car is not firing on the first two cylinders

This is generally related to spark problems when it is more consistent. Spark related problems generally will result from things like ignition coils, crankshaft position sensor, spark plugs, spark plug wires or ignition modules not working properly. As you know,...

Related articles

Is a Keyless Push-Button Ignition More Reliable?
Vehicle Vehicle starting systems have evolved significantly since their inception. When automobiles were initially introduced, you had to manually crank the engine over with a handle on the front of your engine compartment. The next phase involved a lock and...
What Is the Difference Between Conventional, Electronic and Distributor-less Ignition Systems?
If If you’re like many people, you know that when you turn the key in your ignition, the engine cranks and you’re able to drive your car. However, you might not know how that ignition system works. For that matter,...
Symptoms of Bad or Failing Spark Plugs
Common signs of faulty spark plugs include slow acceleration, loss of power, poor fuel economy, engine misfires, and difficulty starting the car.