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.

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How do you import an entire phonebook from your phone to the HandsFreeLink?

First, note that only certain cell phones can export the phonebook. Second, understand that this feature is only available on Accords with the navigation system. If that sounds like your situation, then all you need to do is follow the...

What steps should I take to troubleshoot a problem connection with the Auxiliary input jack?

While Ford has made it as simple as possible to connect a portable music player to your car’s radio, there are a few problems that might crop up. Follow the tips below to troubleshoot the system: Make sure you’re...

Car drifts when driving.

Hi, it sounds like you may have something worn out in the front end. It could be a ball joint control arm, or tie-rod end. If it was the steering box (rack and pinion) you may have a lot of...

Taillights and brake lights don't work

The multifunction switch has a manufacturer recall that is active on the switch since 2011. The switch may be the cause of all lights on the rear to fail. The recall ID is 11V352000, and is dated 7/13/2011. I recommend...

Ignition wouldnt turn tried to jimmy steering wheel now steering locked and unable to unlock

Try another key if you have one. If you have no other key then try and get another one cut from the one you have. The key you have could be worn and not working. A fresh cut key may...

Car starts, but quits; removing/replacing battery cable helps

Hello there, thank you for asking about your 2002 Chrysler Intrepid. You're correct in that a transmission mechanical problem would not come and go by simply disconnecting the battery. My guess is that the transmission shift solenoid pack has failed....

when i accelerate the stationary car in first gear then car vibrates.

Hello. Most of the time this is a drive shaft issue. I would check the coupling joints to see if they are worn out. Most of the time they will be and they will need to be replaced. I have...

Check Engine Light, dealership quoted me for a coolant control valve replacement.

Hi there, thanks for writing in. The coolant control valve controls the flow of coolant to the engine, the storage tank, and the heater core. A fault with this valve could prevent proper engine starting and reduce your fuel economy...

car dome light wont go off with key in the ignition cant turn dome light on maumally every frw day car has to be jumped off

Hello, thank you for writing in. The dome light is triggered by several different switches, and one of them is stuck on. One thing you can do until you diagnose the issue, is unplug the fuse for the light. This...

Related articles

How a Keyless Push-Button Ignition Works
Technology Technology has advanced for automotive security and user-focused features, and a shift is occurring where traditional key-and-cylinder starting systems are being replaced by keyless push-button ignition systems. They are incredibly simple to operate and provide excellent security. The system...
A Buyer’s Guide to the 2012 Mercedes-Benz E-Class
The The Mercedes-Benz E-Class is a midsize luxury vehicle that has been one of the most popular options for a number of years. The 2012 models, which now include a coupe, a wagon, and a convertible as well as the...
How Long Does an Ignition Ignitor Last?
The The ignition system of a car is responsible for kicking off the combustion process. Without the ignition coil on your car giving off the necessary spark, the air and fuel mixture in your engine will not be able to...