The Top 6 Reasons for Poor Vehicle Acceleration

One concern we hear a lot about here at Accurate Service is vehicle acceleration.


Many high-mileage vehicles will experience symptoms of poor acceleration. You may not notice them under regular circumstances*, but they will be clear when you are driving uphill or when you need to accelerate quickly in highway traffic.

These are the top six reasons for poor vehicle acceleration:

TPS Malfunction

The throttle position sensor (TPS) detects the angle of the throttle valve opening which is controlled by the accelerator pedal and sends this data to the engine ECU. If it malfunctions, the engine speed cannot be controlled by the accelerator pedal.

Problem with the Air Flow Meter

The air flow meter measures the mass of the air that flows into the inlet air cleaner. It then sends this information to the engine ECU to calculate the air/fuel mixture. If the air flow meter is malfunctioning, it can result in acceleration problems.

Malfunctioning Oxygen Sensor

The oxygen sensor monitors the exhaust emissions your vehicle makes. It evaluates the air/fuel ratio that goes through the engine. If the sensor is damaged, your vehicle will not know what amount of air/fuel mixture to take in which could result in a mixture that is rich in fuel. This will result in slow vehicle acceleration- even when the pedal is completely pressed.

Clogged/Dirty Fuel Filter

When the fuel filter is dirty or clogged, the engine will not receive the proper amount of fuel that it needs to operate correctly. This results in poor acceleration, or perhaps no acceleration at all. Be sure to have your fuel filters changed per the intervals set in your vehicle’s owner’s manual.

Clogged/Dirty Air Filter

The fuel filter provides the engine with clean fuel and the air filter provides the engine with clean air for the air/fuel mixture that is sent to the combustion chambers. If the air filter is clogged, the engine won’t receive the correct air/fuel mixture resulting in poor acceleration. Air filter replacement is a regular maintenance item and should be done per the intervals laid out in your owner’s manual.

Loose or Worn Timing Belt

When you accelerate the wheels will turn and increase your RPM, straining the timing belt. If the timing belt is worn or off by even one tooth it can cause acceleration to hesitate or even fail.

The above list consists of only the most common reasons we encounter for poor acceleration. The list, however, does not end there. Other culprits may include a slipping clutch or a problem with the transmission system. If you would like to know more or need any assistance with your vehicle, give us a call! We are happy to help you. Call 520.441.4744 or schedule your appointment online.

*If you notice poor acceleration upon take off, don’t panic and jump to the conclusion that something is wrong with your vehicle. When acceleration is difficult when you first try to drive your vehicle it usually means one of two things. Either your emergency brake is on or you are in neutral. Both are easy and common mistakes to make. Simply undo the brake or put your car into the proper gear and you should be fine.