Engine shaking, sluggish acceleration? The root cause may lie in the spark plugs

When your beloved car starts to vibrate inexplicably, especially while waiting at a red light, feeling like the entire body is constantly buckling; when you press the accelerator hard but don't experience the expected rapid acceleration, that feeling of powerlessness is truly frustrating.

When encountering these problems, many car owners first think of complex fuel systems, expensive sensors, or even internal engine malfunctions. But you might not realize that a seemingly insignificant and inexpensive component—the spark plug—is often the culprit behind these issues.

Why can such a small spark plug cause such a big commotion?
Imagine that the engine cylinder is like a miniature explosion chamber. The spark plug's job is to generate a strong electric spark at the most precise moment, igniting the air-fuel mixture, causing an explosion, and thus pushing the piston to move, providing power to the car.
This "ignition" action must be precise, powerful, and continuous. When spark plugs fail or are in poor condition, this delicate combustion process is disrupted, manifesting as: Ignition failure: The spark plug in a particular cylinder fails to produce a spark, causing that cylinder to do no work.
Insufficient ignition energy: The spark is too weak to fully and quickly ignite the air-fuel mixture, resulting in incomplete combustion.
Inaccurate ignition timing: Wear on the spark plug electrodes can cause changes in the ignition gap, affecting ignition timing.
These failed ignitions directly lead to noticeable engine vibration, weak acceleration, and increased fuel consumption.

How to determine if spark plugs are the culprit?
In addition to the typical symptoms mentioned above, you can also use the following to help determine the problem:
Difficulty starting: The starter motor takes longer to start, and the engine feels clunky.
Unstable idling: The engine speed fluctuates when the engine is stationary, and the vehicle vibrates more.
Increased fuel consumption: Due to decreased combustion efficiency, the engine needs to inject more fuel to maintain power.
Jerking while driving: Especially during low-speed acceleration, the vehicle may experience a jerky, jerky sensation.
If you experience several of the above symptoms, the spark plugs are highly likely the culprit.

Prevention is better than cure: How to choose and replace spark plugs?
Spark plugs are consumables with a fixed lifespan. Timely replacement is the best strategy to avoid the above problems.

1. When to replace?
Please refer to your vehicle's owner's manual. The manufacturer will provide a specific replacement interval. Generally speaking:
Standard nickel alloy spark plugs: Approximately 20,000-30,000 kilometers
Platinum spark plugs: Approximately 40,000-60,000 kilometers
Iridium spark plugs: Approximately 60,000-100,000 kilometers or even longer
Note: This is just a general recommendation. If you frequently drive at low speeds in urban areas and experience frequent stop-and-go traffic, the replacement interval should be shortened accordingly.

2. How to choose spark plugs?
Replacing spark plugs is not about "the more expensive the better," but rather "the most suitable one is the best."
Material is key: From durable nickel alloys to higher-performance platinum, and then to iridium for the longest lifespan and best ignition performance, the material directly determines the spark plug's lifespan and performance. For most passenger cars, platinum or iridium spark plugs are a cost-effective upgrade option.
Heat range must match: You must choose spark plugs with the same heat range specified by your engine manufacturer; otherwise, it will affect the engine's normal operation.
The safest approach is to inform a professional mechanic of the specifications in your vehicle's owner's manual, and they will recommend and install the most suitable products for you.