What are the reasons for a car lacking power and high fuel consumption?

[Yvette]

The reasons for a car lacking power and high fuel consumption are as follows: Fuel system malfunction: A clogged or waterlogged air filter reduces air intake, leading to an overly rich air-fuel mixture, incomplete engine combustion, and poor acceleration. In this case, the exhaust pipe emits heavy black smoke. Cracks in the fuel line or loose connections causing air leaks, along with insufficient fuel pump pressure, result in poor fuel supply and affect acceleration performance. Electrical system malfunction: Issues with the air flow meter reduce air intake, causing the air-fuel mixture to be either too rich or too lean, affecting acceleration performance. Damage to individual cylinder spark plugs, meaning a misfiring cylinder, impacts acceleration performance. Overheating or a faulty temperature sensor also affects acceleration performance. A clogged catalytic converter or a faulty oxygen sensor can cause poor engine acceleration. Mechanical malfunction: Wear and tear on engine valves, cylinder liners, pistons, and rings lead to insufficient cylinder pressure. Excessive intake valve clearance, insufficient exhaust valve clearance, or damaged intake and exhaust valves can cause misfiring cylinders, affecting acceleration performance. Wear on the timing belt (chain), causing ignition timing to be either too early or too late, also impacts acceleration performance.

[LeClayton]

Over the years of driving, I've encountered several instances where my car lacked power and had high fuel consumption. This is usually due to a dirty air filter clogging the intake, preventing the engine from getting enough air for proper combustion, which naturally leads to soaring fuel consumption and reduced power. For example, just last week after cleaning the filter, the car ran much smoother. Worn-out spark plugs are another common factor, as incomplete ignition leads to incomplete combustion. Additionally, insufficient tire pressure increases rolling resistance, making the car sluggish and increasing fuel consumption, so it's advisable to regularly check and maintain tire pressure at the recommended value. If the problem persists, it might be due to severe carbon buildup or fuel system issues, such as clogged fuel injectors or a faulty fuel pump. It's best to visit a repair shop early for professional equipment diagnostics. Developing a habit of servicing the car every six months can effectively prevent these issues, prolong the vehicle's lifespan, and avoid unexpected expenses.

[StRyder]

From a technical automotive perspective, insufficient vehicle power accompanied by high fuel consumption is often caused by declining engine efficiency. A faulty mass air flow sensor can disrupt the air-fuel ratio, creating excessively rich or lean mixtures that increase fuel consumption and reduce power. Aging oxygen sensors fail to accurately regulate emissions, causing the ECU to make incorrect judgments that worsen fuel economy. Worn spark plugs with increased gaps cause delayed ignition and incomplete combustion, leading to carbon buildup and a vicious cycle. A clogged catalytic converter also increases exhaust backpressure, resulting in additional fuel consumption and overall performance degradation. Routine OBD scanner diagnostics can help identify issues through trouble codes. Regular maintenance such as replacing filters, keeping the throttle body clean, optimizing the ignition system, and maintaining exhaust pathways can significantly improve performance. Additionally, avoiding aggressive driving habits like sudden acceleration and low-speed towing can prevent further deterioration.

[EmmanuelFitz]

Having driven for most of my life, I've seen many cars with weak performance and high fuel consumption issues, mostly caused by engine carbon deposits. Internal dirt increases, compression ratio changes, combustion efficiency drops, fuel consumption rises, and power becomes insufficient. In the past, simply replacing spark plugs would do, but now with more vehicle electronics, it's essential to pay attention to sensors like oxygen sensors failing, which affects detection accuracy and accelerates fuel consumption. Low tire pressure increases rolling resistance, wasting fuel unnecessarily. It's recommended to regularly drive on highways to clean carbon deposits, use good fuel additives, opt for low-viscosity oil to maintain system lubrication, and develop the habit of checking tire pressure every 5,000 kilometers. Addressing minor issues early can save fuel costs and ensure safe driving.