What are the reasons for lack of power in 4th and 5th gears?
2 Answers
The reasons for lack of power in 4th and 5th gears are as follows: Throttle Position Sensor Malfunction: When the accelerator pedal is pressed, the cable drives the throttle valve, which is the throttle. The throttle valve is equipped with a position sensor. The control unit uses the signal from the throttle position sensor to determine the throttle opening and then calculates the corresponding signal voltage. Finally, the vehicle's fuel injection volume is calculated based on this signal voltage. Therefore, if the throttle position sensor is dirty or the voltage is unbalanced, it can lead to electronic throttle failure, resulting in the situation where the speed does not increase even when the accelerator pedal is fully pressed. Engine Malfunction: Among the three systems of the engine—intake, fuel, and ignition—the throttle position sensor signal, as mentioned earlier, is actually part of the intake system. For the engine to operate normally, it requires sufficient air. If there is a leak or blockage in the intake system, the car may experience reduced power, inability to increase RPM, and body shaking when the accelerator pedal is pressed.
I found that when the car lacks power in fourth or fifth gear, there could be several possible reasons. The most common one is insufficient engine output, such as issues with the fuel supply system—like an aging fuel pump or clogged fuel injectors—which become more noticeable at high RPMs. Another possibility is a faulty ignition system, where carbon buildup on the spark plugs or loose wiring can affect ignition efficiency. Additionally, a dirty air filter can restrict airflow, leading to a lean air-fuel mixture and naturally reduced power. Transmission issues shouldn’t be overlooked either; a severely worn clutch can slip, especially noticeable during hard acceleration in manual transmission cars. The electronic control unit (ECU) might also limit power output if it falsely reports trouble codes. I recommend starting with simple checks, such as changing the engine oil and cleaning the air filter. If the problem persists, it’s best to visit a professional shop for a thorough diagnosis—after all, safety comes first, and losing power on the highway is no small matter.
