Motoring: Why your car won't accelerate and what to look out for

A sluggish response when you press the accelerator can be frustrating and worrisome.

Several factors could be responsible for poor acceleration, and many of them are related to engine components that manage airflow, fuel delivery, and combustion. This week on Motoring, we delve into some common causes and what you can do about them.

Clogged air filter

One of the most frequent culprits behind slow acceleration is a blocked air filter that is under the hood. When the air filter is clogged, less air can reach the engine, limiting the car's performance.

Before calling your mechanic, try checking and replacing the air filter if your vehicle feels sluggish. The problem could be right there.

Airflow sensor (MAF)

The mass airflow sensor (MAF) plays a critical role in regulating the air-fuel mixture by measuring the air entering the engine.

With time, dirt and dust can accumulate on the MAF, causing it to send incorrect readings to the engine control unit. This can lead to poor acceleration or even stalling. It is possible to get a dirty MAF cleaned and if the problem persists, it is advisable for replacement.

Oxygen sensor

The oxygen sensor is responsible for monitoring the air-fuel ratio by measuring the amount of oxygen in the exhaust.

A malfunctioning oxygen sensor can throw off this balance, resulting in sluggish acceleration and increased fuel consumption. This can as well be cleaned but needs proper handling.

Worn spark plugs

Spark plugs are key for igniting the air-fuel mixture in the engine.

Overused or faulty spark plugs can cause misfires, leading to decreased power and poor acceleration. Also the brand that one chooses for the car’s engine really matters.

It is always key to replace the plugs during routine maintenance or service of the car to archive engine performance.

Below are some of the signs that indicate faulty spark plugs.

Difficulty in starting the engine: Faulty spark plugs can struggle to generate the necessary spark to ignite the engine. If you notice that your car takes longer than usual to start, or you have to turn the key multiple times, your spark plugs could be the issue.

Engine misfires: The engine will always misfire when the combustion process is incomplete. You can always tell a misfire when there is a rough or uneven engine operation. The car might as well jerk as you drive.

Poor acceleration: Without a strong spark, the engine can't produce enough power to accelerate efficiently. These can result in making the car sluggish.

Rough idling: A properly functioning engine should idle smoothly when the vehicle is stopped. If the engine is vibrating, shuddering, or making unusual noises at idle, it could be a sign that one or more spark plugs are failing.

Increased fuel consumption: Bad spark plugs can cause incomplete combustion, meaning your engine will burn more fuel than necessary. Always check them out.

Blocked catalytic converter: The catalytic converter is responsible for reducing harmful emissions by converting toxic gases into less harmful ones.

With time, it can become clogged, which restricts exhaust flow and hampers engine performance. If the catalytic converter is blocked, your car may struggle to accelerate. This can sometimes lead to emission of black smoke from the exhaust.

Fuel system issues: The fuel system plays a key role in supplying fuel to the engine for combustion. Several components within the system can fail, causing poor acceleration.

Clogged fuel injectors: Fuel injectors regulate how much fuel enters the engine’s combustion chamber. Over time, they can become clogged with contaminants, disrupting fuel delivery and reducing power.

Faulty fuel pump: The fuel pump is responsible for transporting fuel from the tank at the end to the engine at the front.

A failing fuel pump can result in insufficient fuel reaching the engine, causing sluggish acceleration or even a complete breakdown.

If you’re experiencing slow acceleration in your vehicle, it's crucial to address these potential issues promptly to avoid further damage and maintain optimal performance.

Regular maintenance of your vehicle and timely repairs are key to keeping your car running smoothly.