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Q: The car accelerates slowly, hesitates and shudders

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My car started having some issue the other day, while I was driving and tried to accelerate very quickly. The car seemed to lose power and there was a delay in picking up speed. The engine hesitated and if I attempted to accelerate more, it would shudder. The problem is the same if the car idles at the red stop and I try to accelerate. I fear that it would stall, so in those situations I put it in park just in case. Occasionally, the engine seems to gather the speed quickly and but the car wouldn't run fine afterward. It would then hesitate and shudder yet again. The check engine light is on as well. The car shakes only when it is put in drive, not while I accelerate from neutral. I had the spark plugs replaced. What is causing these issues? Is it a serious engine problem?

Unmetered air can cause this type of hesitation and shuddering. Too much air compared to fuel will cause a lean misfiring condition. Fault codes need to be read out of your Mercedes C320’s engine computer to see if there are any underlying issues and those issues are corrected.

The induction should be inspected and checked for vacuum leaks. Also, fuel pressure and volume should be checked as well if the induction system checks out okay. A partially clogged fuel filter can cause a starvation issue on heavy acceleration. You may want to enlist the help of a mechanic, such as one from YourMechanic, who will have the tools and expertise to conduct this type of diagnosis and repair for your acceleration issue.

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