What causes the car to feel sluggish and fail to accelerate when the throttle is pressed hard?
2 Answers
When a car feels sluggish and fails to accelerate upon pressing the throttle hard, it may be due to reasons such as excessive engine oil or overly high oil viscosity. Below is relevant information: 1. Poor fuel quality: Shortly after refueling, the engine warning light on the dashboard illuminates. This is usually caused by adding low-quality gasoline from non-standard gas stations, leading to insufficient combustion of the air-fuel mixture during engine operation and triggering the engine warning light. While this does not affect driving safety, it may harm the engine to some extent. 2. Oxygen sensor malfunction: Modern cars are equipped with two oxygen sensors, one before and one after the three-way catalytic converter. The front oxygen sensor detects the air-fuel ratio under different engine conditions, and the ECU adjusts fuel injection and calculates ignition timing based on this signal. The rear sensor primarily monitors the performance of the three-way catalytic converter. Therefore, if the oxygen sensor is damaged or the sensor connector is faulty or loose, it may cause the air-fuel mixture to become too lean or too rich.
I've repaired many cars in my lifetime, and encountering sluggish acceleration when stepping hard on the gas pedal is all too common. Usually, it's an issue with the intake system—like when the air filter is completely clogged, preventing fresh air from entering, causing incomplete fuel combustion, making the engine struggle when you floor it. There could also be fuel system problems, such as insufficient fuel pump pressure or clogged fuel injectors, leading to inadequate fuel delivery and naturally resulting in poor performance. Ignition system issues, like worn-out spark plugs failing to ignite properly, or a blocked catalytic converter in the exhaust system trapping exhaust gases, can also slow down acceleration. If the car's ECU is misconfigured or has excessive carbon buildup, it might automatically reduce engine power for protection. All these issues can easily lead to poor acceleration, so it's best to promptly visit a professional shop to check intake airflow, fuel pressure, and electrical circuits to avoid costly major repairs.
