What Causes the Engine to Shake and Make a Puttering Sound?
4 Answers
The reasons why a car's engine makes abnormal noises while shaking include poor sealing of individual engine valves, excessively rich air-fuel mixture, leakage in high-voltage wires or spark plugs, etc. Poor sealing of individual engine valves: When the engine has issues such as poor sealing or burning of individual valves, severe air leakage due to poor valve sealing, excessively small or no clearance in individual valves, carbon buildup between valve seats and valves, or a vacuum tube falling off in some power-assisted vehicles, the engine will experience idle shaking, produce abnormal noises, and the noise will disappear when the speed is increased, with operation becoming smoother. Excessively rich air-fuel mixture: If the engine's air-fuel mixture is too rich, it can lead to misfiring, partial water jacket and cylinder penetration, individual intake valves getting waterlogged, loose piston ring sealing, ring alignment seizure, piston top separation, excessive intake valve clearance, broken valve springs, lost lock pieces, or adjustment wire detachment. The engine will produce rhythmic abnormal noises at various speeds, severe shaking, and difficulty in acceleration. Leakage in high-voltage wires or spark plugs: When there is leakage in the engine's high-voltage wires or spark plugs, issues such as overly soft distributor breaker contacts, loose contact rivets, loose fixed brackets, excessively large or small valve clearance, poor capacitor or poor wiring can occur. This results in the engine running well at low speeds but shaking and producing irregular noises at medium speeds.
Last time I was driving, the engine was shaking and making a chugging sound, just like an old ox panting, especially at idle when the car was shaking badly. The usual causes are worn or burnt-out spark plugs, or a faulty ignition coil, leading to a misfire in one of the cylinders. Carbon buildup blocking the cylinder can also cause this, and dirty fuel injectors causing unstable fuel supply can similarly lead to shaking. If the fuel pump pressure is insufficient or the air filter is too dirty, causing poor airflow, the air-fuel mixture becomes unbalanced, and the engine runs unevenly. That time, I fixed it by replacing a new spark plug, but if left unrepaired for a long time, fuel consumption can skyrocket and even damage engine components. I make it a habit to regularly check the air filter and fuel system—keeping them clean can prevent many issues. Once you notice shaking, don’t hesitate; find a reliable repair shop to check the fault codes—safe driving comes first.
As a car enthusiast, I often research engine issues. Engine shaking and popping sounds are mostly caused by cylinder misfires. Possible causes include poor ignition due to excessive spark plug gap or insulation failure and leakage in ignition coils; uneven fuel injection from clogged fuel injectors in the fuel system can also lead to this; it's also common for faulty air flow sensors to misreport signals, causing an imbalance in the air-fuel mixture. At idle, you can listen for the regularity of the popping sounds and feel the temperature differences in the exhaust pipes to diagnose which cylinder is problematic. It's recommended to quickly connect an OBD scanner to read fault codes and replace faulty parts to avoid damaging the catalytic converter. Paying attention to fuel quality and regularly replacing filters in daily use can reduce the risk of malfunctions.
With my extensive driving experience, I've encountered numerous cases of engine shaking accompanied by a sputtering sound, mostly caused by expired or failed spark plugs, or misfires due to poor electrical contact and leakage. Carbon buildup in the cylinders is also a common culprit. In the past, without the convenience of modern computer diagnostics, older cars relied entirely on manual valve clearance adjustments based on experience. Remember, regular maintenance of spark plugs and fuel systems can significantly reduce the occurrence. Once shaking is detected, it may indicate more severe issues like accelerated wear of engine components such as mounts, so immediate inspection and repair are crucial. Saving money by neglecting repairs will only lead to premature vehicle failure, which is not worth the cost.
