What are the reasons why a car cannot accelerate?
2 Answers
The reasons why a car cannot accelerate: 1. The three-way catalytic converter is clogged, and poor exhaust flow can affect the car's power, preventing the car from speeding up. Exhaust blockage often occurs when the three-way catalytic converter is clogged; 2. The thickness of the clutch plate decreases. As the clutch plate wears more severely, the clutch pedal will rise higher, and the phenomenon of the car not being able to speed up will also occur; 3. Poor signal from the front oxygen sensor. The front oxygen sensor is responsible for detecting the oxygen concentration in the exhaust, allowing the ECU to promptly adjust the air-fuel mixture ratio for precise fuel injection control. When the air-fuel mixture occasionally does not burn completely, the exhaust will contain a large amount of carbon deposits, polluting the front oxygen sensor inserted into the exhaust pipe. Incomplete combustion of the air-fuel mixture can occur during cold starts, idling to warm up the car, idling, or even during sudden acceleration.
I've been repairing cars for most of my life, and I've seen plenty of cases where cars can't accelerate. The most common issue is with the fuel system—like when the fuel pump stops delivering fuel or the filter is severely clogged, preventing fuel from reaching the engine, which naturally makes the car sluggish. Dirty or faulty spark plugs can cause unstable ignition, making the car jerk during acceleration. The air system is also crucial; if the mass airflow sensor malfunctions, the ECU misjudges the air intake, limiting power. Transmission problems are also frequent—worn-out clutches in manual cars can slip, while issues with the torque converter in automatics can slow down response. A clogged exhaust system, such as a blocked catalytic converter, can also hinder acceleration due to poor exhaust flow. Safety first: if you notice your car can't accelerate while driving, pull over immediately—don't push it—and get it checked by a professional as soon as possible. Regular maintenance, like oil and filter changes, is key—prevention is better than dealing with problems later.
