What Causes Poor Acceleration and Loud Engine Noise?

[JasonRose]

It may be due to excessive carbon buildup inside the engine or prolonged failure to change the engine oil. Detailed explanations of the causes and solutions for loud engine noise are provided below: Detailed causes of loud engine noise: All engines have a compression ratio. If carbon deposits accumulate on the piston crown, it will increase the engine's compression ratio. An increased compression ratio can cause knocking during engine operation, leading to reduced power output and increased fuel consumption. Engine oil serves multiple functions including lubrication, cleaning, sealing, heat dissipation, cushioning, and rust prevention. Prolonged failure to change the oil can increase internal engine resistance and accelerate engine wear. Solutions for loud engine noise: Clean the throttle body. After prolonged vehicle use, the throttle body may accumulate dirt. If engine noise becomes excessively loud, it might be due to a dirty throttle body - professional cleaning at a repair shop can significantly improve the situation. Sound insulation improvement. The noise issue might also stem from deteriorated sound insulation performance. As various soundproofing materials age, previously inaudible sounds may penetrate the cabin. Therefore, upgrading sound insulation can effectively reduce noise levels.

[McJaxon]

Poor acceleration accompanied by loud engine noise may indicate issues with the engine itself or related components. I've seen many vehicles exhibit these symptoms, with the most common cause being engine misfire due to uneven cylinder operation—such as a worn spark plug or faulty ignition coil in one cylinder, leading to uneven combustion, insufficient power output, and increased noise. Another potential cause is inadequate fuel supply from the fuel system, like low fuel pump pressure or clogged fuel injectors, which prevents sufficient fuel delivery, forcing the engine to work harder and produce louder noise. A dirty air filter restricting airflow or an exhaust leak generating additional noise could also be culprits. Additionally, transmission issues like clutch slippage can cause poor acceleration, making the engine sound like it's roaring. I recommend starting with simple checks: inspect the air filter for replacement, try changing the spark plugs, or listen for abnormal exhaust sounds. If the problem persists, a full inspection at a repair shop is advisable to prevent long-term damage affecting engine lifespan. Timely action is crucial—don't delay until a highway breakdown occurs.

[OLyla]

Lack of acceleration accompanied by unusually loud engine noise is a fairly common issue – I've encountered it several times with my own older car. Typically, this stems from drivetrain problems. For instance, when the clutch is worn and slipping, you'll notice sluggish acceleration while the engine revs spike with increased noise. Alternatively, insufficient transmission fluid can cause delayed gear shifts. Another possibility lies in engine accessory issues, such as damaged water pump or power steering pump bearings creating excessive friction noise. Heavy load situations like aggressive acceleration uphill can also force the engine to work harder, generating loud noise. My first step is always checking the dipstick for oil level and quality – overdue oil changes with dirty oil increase engine strain and noise. Never skimp on routine maintenance like oil and air filter changes; these small expenses prevent many problems. When these symptoms appear, stay calm, drive gently to a repair shop, and let mechanics scan for trouble codes – often a minor fix solves it. Safety comes first; never push a struggling car to avoid roadside breakdowns.

[McJace]

If the car lacks acceleration power and the engine is excessively noisy, it could be caused by several core issues. One possibility is a malfunction in the ignition system, such as carbon buildup on the spark plugs leading to poor ignition, resulting in reduced power output but increased noise. Another issue could be fuel-related, like low-quality gasoline causing knocking or inefficient combustion, making the engine sound strained during acceleration. A leaking exhaust system or a clogged catalytic converter can also produce similar symptoms—loud noise but weak performance. Additionally, engine wear, such as excessive valve clearance or faulty components, may contribute to the problem. I recommend a simple diagnosis: pay attention to any knocking sounds or smoke while driving, then check the spark plugs and exhaust system. Regular maintenance, such as using high-quality fuel and replacing air and oil filters periodically, can help reduce risks. Don’t ignore this issue—early repairs ensure peace of mind.