What Causes a Car to Shake When Accelerating but Not at Idle?

[StEmiliano]

The reasons why a car shakes when accelerating but not at idle are as follows: Excessive Carbon Buildup: When there is excessive carbon buildup in the throttle body, fuel injectors, or intake manifold, or when there is too much carbon inside the engine, it can cause the engine to shake. Solution: Clean the internal components of the engine. Low Cylinder Pressure: After prolonged use, the gaps between each cylinder liner and piston may become inconsistent, reducing power output and causing low oil pressure and cylinder pressure, leading to insufficient power and engine shaking. Solution: Reduce the gaps between the cylinder liners. Faulty Ignition Coil: If the ignition coil fails, it can result in insufficient or weak spark plug ignition, leading to engine misfires, difficulty starting, and shaking during acceleration. Solution: Replace the ignition coil.

[SanLouis]

Oh, this problem sounds just like the kind of issue my old car often gives me trouble with. If it doesn't shake at idle, it means the engine is basically running normally, but when you step on the gas to accelerate, it starts to shudder. This is usually due to a problem with the ignition system. The most common culprits are aging spark plugs or severe carbon buildup, which can't keep up with the ignition efficiency during acceleration, leading to poor performance in some cylinders. It could also be an issue with the high-voltage ignition coils, which tend to fail under high load. Another frequent offender is clogged fuel injectors, which can't supply fuel evenly during acceleration, causing irregular vibrations. It's also worth checking the engine mounts—if they're loose, they can worsen the shaking under dynamic loads. I recommend not waiting until fuel consumption skyrockets or the car breaks down halfway before addressing the issue. Take it to a repair shop to check the spark plugs and fuel system, and regular maintenance can prevent these problems. Ignoring them for too long can also affect the exhaust system, and then the repair costs won't be worth it.

[DamianAnn]

I encountered this issue with my car last year. The idle was perfectly stable without any problems, but as soon as I stepped on the gas, the car would shake, and the entire steering wheel would vibrate. Later, when I took it in for repairs, I found out the main culprit was the fuel injector—it was clogged, causing uneven fuel distribution during acceleration, making the engine struggle under heavy load. Another potential culprit is an inaccurate mass airflow sensor, which can't precisely calculate the air intake when accelerating, leading to an imbalanced air-fuel mixture. If the fuel pump pressure is insufficient, it can also cause uneven fuel supply during acceleration. This repair taught me the importance of regular cleaning and maintenance of these components. Otherwise, you might not notice until the engine light comes on, which not only causes delays but also wastes fuel. Now, during maintenance, I always ask the mechanic to check these sensitive points to ensure a smoother ride.

[AnastasiaMarie]

I was really confused when I first encountered this issue while learning to drive. The car idles fine but shakes when accelerating. After researching, I found out the common causes are ignition system failures. Over time, spark plug gaps widen, causing weak sparks at high RPMs, leading to uneven engine combustion and vibrations. Another possibility is clogged fuel injectors due to carbon buildup - when accelerating, fuel supply can't keep up, creating an imbalance between air and fuel mixture. Transmission linkage issues could also cause uneven power delivery. For beginners, I suggest checking the dashboard for warning lights and getting it repaired early. Avoid DIY disassembly as it may damage more components.