What causes lack of power when accelerating in 4th and 5th gears?

[Ann]

The reasons for lack of power when accelerating in 4th and 5th gears are as follows: 1. Clutch slipping: The main manifestation is that when accelerating while driving, the vehicle speed cannot increase with the rise of engine RPM, and the engine power cannot be fully transmitted to the drive wheels, resulting in weak driving performance, especially noticeable when going uphill. The main cause of clutch slipping is insufficient friction on the clutch friction plate. 2. Forced gear shifting or disengagement before full clutch engagement: Prolonged driving with the clutch partially engaged, coasting with the clutch depressed; incomplete gear engagement or disengagement, where sudden throttle application occurs before the gear is fully engaged or disengaged, causing abnormal wear on the clutch plate. 3. Engine issues: The power source comes from fuel combustion, and the engine is responsible for supplying fuel and converting chemical energy into mechanical energy. Therefore, when experiencing weak acceleration and slow speed increase, the engine system should also be a key focus for inspection.

[ODonovan]

I've been driving manual transmission cars for years and have encountered situations where the car feels sluggish when accelerating in fourth or fifth gear. This is quite common, especially when higher gears require more torque but the engine can't deliver enough power. The reasons can be: first, issues with the fuel system, such as a clogged fuel filter or a malfunctioning fuel pump, leading to insufficient fuel supply and weak power. Second, ignition system problems, like worn-out spark plugs or faulty ignition coils, causing incomplete combustion. Third, clutch slippage, where significant power loss occurs during semi-engagement. I once found out that a clogged exhaust pipe was the culprit, as restricted exhaust flow affected overall performance. If this happens, don't delay—slow down and stop immediately, then head to a repair shop for diagnosis. Continuing to drive at high speeds can be dangerous and lead to accidents, disrupting your trip and posing risks. In short, start by checking simple components like filters and spark plugs. If that doesn't solve the problem, let professionals handle it—safety first.

[McLouis]

As an average car owner, I recently noticed my car lacked power when accelerating in high gear and promptly investigated the cause. High gears require strong power output, potentially involving restricted air intake or exhaust—such as a dirty air filter hindering sufficient airflow or excessive carbon buildup in the throttle body obstructing gas passage. Additionally, fuel injection issues like clogged injectors or insufficient fuel pressure are common culprits. On the transmission side, worn gear synchronizers or slipping clutch plates can prevent power from reaching the wheels. I’ve also heard ECU control problems, such as faulty sensors, may limit output. For a quick DIY check, inspect the air filter and fuel system. If unresolved, immediately scan OBD trouble codes and seek professional repair if needed to avoid high-speed hazards and ensure smooth drives every time.

[HaleyFitz]

My driving experience tells me that the lack of power when accelerating in fourth and fifth gears is likely due to issues with the engine and transmission. Insufficient fuel supply, such as a failing fuel pump or clogged injectors, is a common cause—poor combustion leads to weak power. Ignition problems like bad spark plugs or faulty coils could also be the culprit. Clutch slippage is a widespread issue, especially noticeable in higher gears when power drops. Carbon buildup in the cylinders can also reduce performance. Start by checking simple fixes like replacing the air filter, and if that doesn’t help, take it to a repair shop immediately—don’t risk driving it hard.