Why does the engine idle normally but lack power when running?

[McLyla]

Here is the relevant introduction to the situation where the engine idles normally but lacks power when running: Carbon buildup in the vehicle: There are three reasons for the car's lack of acceleration power. The first is carbon buildup in areas such as the valves, idle control valve, intake manifold, combustion chamber, and spark plugs. Insufficient fuel supply is caused by severe clogging of the fuel injectors. Poor fuel quality: One of the most important reasons for a car's lack of acceleration power, which many car owners experience, is the use of poor-quality fuel. This can affect the fuel filter and fuel lines, potentially leading to inadequate fuel supply and resulting in a lack of acceleration power.

[DeChristopher]

I just encountered a similar issue with my car. It idles smoothly, but once I hit the road, it feels sluggish and lacks power, a far cry from its previous performance. After some thought, I realized it might be due to a clogged fuel line or a dirty air filter, preventing proper fuel combustion. Sometimes, worn-out spark plugs or faulty ignition coils can also make acceleration feel weak. Another common cause is a clogged catalytic converter, which restricts exhaust flow. Back then, I took it to the shop to check the fuel pump, and sure enough, it was on its last legs. I recommend inspecting these simpler areas first—don’t underestimate routine maintenance. Replacing filters isn’t hard and can prevent a lot of trouble. Addressing issues promptly not only restores power but also avoids the danger of breaking down on the road.

[SabrinaFitz]

I usually enjoy tinkering with my car, and it's quite common to experience normal idle but lack of power when driving. Most of the time, it's due to the fuel delivery system not keeping up, such as a faulty fuel pump or a clogged filter, preventing fuel from reaching the engine. The ignition system is also a factor; if the spark plugs are heavily carbon-fouled or the coils are failing, the engine won't fire properly during acceleration. For the exhaust system, check if the catalytic converter is clogged. Simple DIY methods include pulling out the spark plugs to check their color—black indicates combustion issues—and listening for the fuel pump's operation. Ignoring these issues for too long can damage the engine and increase fuel consumption. If you're handy, fixing it yourself can save money and expand your knowledge.

[LillianLee]

Over the years of driving, sudden loss of power is what I fear most—safety comes first. If the idle is normal but the car lacks power while driving, it could be due to insufficient air intake or blocked exhaust, with a dirty air filter being the simplest factor. Sensor failures are also major culprits, such as a faulty oxygen sensor leading to incorrect air-fuel mixture ratios. Clutch slippage can also cause power loss, especially in manual transmission cars. It's best to get it checked at a professional shop immediately; don't risk a major accident to save money. Regular maintenance of filters and fuel lines can prevent most of these issues.