Reasons For a Car Going Slow When Putting On the Gas

by Keith Evans

A properly tuned car should spring to life when the driver presses the accelerator, but some vehicles return only sluggish performance even with the gas pedal fully depressed. Modern vehicles feature a complex set of systems for delivering fuel to the engine and evacuating exhaust gasses, and a failure of any component in these systems can lead to poor acceleration.

Fuel Pump

Automotive experts at 2 Car Pros suggest checking components of the vehicle’s fuel system if the car will not speed up when pressing the accelerator. Under acceleration, the vehicle introduces more fuel into the combustion chamber to increase combustion and boost power output. If something inhibits delivery of fuel to the combustion chamber, the vehicle may hesitate, sputter or simply fail to accelerate. The vehicle’s fuel pump may produce this effect as it starts to fail. Under normal operation, the pump forces fuel from the gas tank, along the fuel rail and into the injectors; as the pump begins to fail, it loses its ability to effectively move fuel and results in decreased acceleration.

Fuel Filter

Like the fuel pump, a clogged fuel filter can inhibit the flow of gasoline and cause the vehicle to not accelerate. As fuel leaves the vehicle’s tank, it passes through a filter designed to remove gasoline impurities. Over time, the fuel filter can accumulate a mass of impurities and become clogged enough to restrict the flow of fuel. As the flow becomes restricted, the vehicle experiences difficulty accelerating. Some vehicles have more than one fuel filter, and a clog in any of the filters can render similar effects.

Fuel Injectors

Once the fuel passes through the fuel pump and filters, injectors move the fuel from the fuel lines into the combustion chamber. Because injectors must maintain very precise control of the amount of fuel introduced into the combustion chamber, they often feature very small passages through which the fuel must pass. Over time, natural buildup and very small impurities in gasoline not removed by the fuel filters can clog holes in the injectors and impede the flow of fuel into the combustion chamber. Automotive experts on 2 Car Pros recommend the occasional use of injector cleaning products available at local automotive parts stores to prevent buildup and restore fuel flow.

Catalytic Converter

On many modern cars, according to the automotive website AA 1 Car, catalytic converters serve to filter pollutants from automotive exhaust gases. Though many causal factors in decreased acceleration occur between the fuel tank and the engine, a clogged catalytic converter can also rob a car of its acceleration. As the catalytic converter becomes clogged with impurities captured from exhaust gases, it builds back-pressure and prevents the free flow of exhaust from the engine’s combustion chamber. Because the engine cannot efficiently evacuate exhaust through a clogged catalytic converter, a car with a bad converter will likely struggle to accelerate.

About the Author

Keith Evans has been writing professionally since 1994 and now works from his office outside of Orlando. He has written for various print and online publications and wrote the book, "Appearances: The Art of Class." Evans holds a Bachelor of Arts in organizational communication from Rollins College and is pursuing a Master of Business Administration in strategic leadership from Andrew Jackson University.

Photo Credits

  • photo_camera car engine image by itsallgood from Fotolia.com