Why does a truck shake at idle but stops shaking when given gas?

[McAbigail]

The reasons why a truck shakes at idle but stops shaking when given gas are: 1. Cracked intake manifold or poor sealing of the intake manifold, etc. When there is a leak in the air supply system, it causes the engine's electronic control unit to receive inaccurate intake air signals, leading to misjudgment and resulting in unstable engine idle; 2. Excessive carbon buildup on the valves and intake pipes; 3. Malfunction of sensors and other circuits controlling the idle; 4. Ignition system failure. In the ignition system, spark plugs are a major component that can cause unstable engine idle. If a spark plug fails to ignite, it directly affects cylinder combustion, causing uneven power output among cylinders and resulting in unstable engine idle.

[Allen]

I've been driving trucks for over ten years, and it's quite common to experience severe shaking at idle that stabilizes once you accelerate. Most likely, it's an issue with the engine's fuel supply system, such as clogged fuel injectors or worn-out spark plugs. At idle, the fuel pressure is low, causing uneven fuel injection and resulting in shaking. When you accelerate, the fuel pressure increases, improving the situation. Another possibility is a sluggish idle control valve, which can cause unstable air intake. Regular maintenance is essential—cleaning the throttle body and replacing spark plugs can help. Otherwise, prolonged shaking can affect the engine's lifespan. Also, check if the engine mounts are loose, as loose fasteners can make idle shaking more noticeable. In short, don't delay—get a professional mechanic to inspect the fuel and ignition systems as soon as possible to ensure driving safety.

[MacCassandra]

I bought a used truck recently, and it shakes badly at idle, but the shaking stops once I accelerate, which really worries me. A friend said it's a common issue—possibly the spark plugs are burnt out or there's a problem with the ignition coils, causing uneven sparks that affect low-speed performance. It could also be due to carbon buildup in the fuel lines, leading to insufficient fuel supply at idle and causing the shaking. He suggested using an OBD scanner to check for error codes first, to see if any sensors are malfunctioning. Also, I should inspect the air filter and fuel injectors and clean them if necessary. Don’t underestimate this issue—prolonged shaking can wear down engine components. I plan to take it to the repair shop next week for a thorough check. Having problems on the highway is no joke.

[MacLorenzo]

As a practitioner in automotive repair, idle shaking that alleviates after acceleration is often rooted in ignition or fuel supply issues. Carbon buildup or aging of spark plugs can cause unstable idle, and the shaking disappears once the throttle is applied and voltage increases. Clogged fuel injectors are also common, where low fuel pressure at idle leads to poor fuel delivery, and cleaning can improve the situation. Insensitive ECU control can also trigger this problem; it's advisable to use diagnostic tools to check for error codes. Additionally, inspect whether the idle control valve is stuck, affecting air flow. Regular maintenance such as changing engine oil and filters can prevent these issues. Overall, it's not complicated, and timely intervention can prevent the fault from escalating.