What Causes Car Shaking During Start-Up?
2 Answers
Reasons for car body shaking after start-up: unstable oil pressure, aging engine components, and severe engine carbon buildup. If the car shakes during start-up, it is recommended to promptly visit a 4S shop for inspection and repair to avoid greater safety hazards. Below are the detailed explanations: Unstable Oil Pressure: Abnormal fuel pump supply pressure or incorrect and poor performance of the intake pressure sensor can cause body shaking. Solution: Check the oil pressure and replace components if necessary. Aging Engine Components: Car shaking is also related to aging engine mounts. Engine mounts are essentially the shock absorption system of the engine, responsible for absorbing minor vibrations during operation. If the engine mounts are faulty, these vibrations will transfer to the steering wheel and the cabin, causing shaking during idle. Solution: Replace engine components. Severe Engine Carbon Buildup: The most common cause of car shaking is a dirty throttle body or excessive carbon buildup in the fuel injectors. When there is too much carbon buildup inside the engine, the gasoline sprayed by the cold start injector will be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts and making it difficult to start. Solution: Clean the fuel system and check if the idle control valve has carbon buildup that needs cleaning.
As an experienced manual transmission driver, I often encounter the issue of car shaking during startup. The most common cause is severe clutch wear—it connects the engine to the transmission, and if the friction disc is worn out, it slips, causing violent shaking when you press the accelerator. Sometimes, the ignition system is at fault, like when spark plugs accumulate too much carbon buildup after prolonged use, leading to misfires in a cylinder and subsequent body vibration. Fuel system problems are also frequent; clogged fuel injectors disrupt smooth fuel delivery, resulting in insufficient fuel supply during startup. Of course, engine mounts should also be checked—if those small parts fail, the engine won’t stay secured, and vibrations transfer to the car body. I recommend checking these during every oil change, and doing simple DIY cleaning of ignition components can help prevent issues. If the shaking is severe, visit a repair shop early—don’t delay like I once did, ending up spending a fortune on a new clutch. This issue is no small matter; it’s tied to safe driving, so take it seriously.
