Why does the car accelerate normally when cold but lacks power when warm?
2 Answers
Here are the possible reasons for the car accelerating normally when cold but lacking power when warm: 1. Engine mechanical system failure: For example, low cylinder pressure leading to reduced engine power, which is more noticeable when the engine is cold, or issues with the intake valve and intake pipe. 2. Excessive carbon deposits: Too much carbon buildup on the intake valve and intake pipe can cause the injected gasoline to be absorbed by the carbon deposits instead of entering the combustion chamber. 3. Engine management system failure: For example, incorrect signals from the water temperature or intake temperature sensors, or wiring faults. 4. Ignition system failure: For example, excessive carbon buildup on spark plugs or incorrect gap settings, leakage in high-voltage wires or distributor caps, or damaged ignition coils. 5. Fuel supply system failure: For example, clogged or improperly closing fuel injectors due to excessive internal carbon deposits.
Last time my car ran fine when cold, but once it warmed up, it felt sluggish when stepping on the gas, as if being held back. This could be due to the fuel pump becoming unstable under high temperatures—aging leads to insufficient fuel supply; or the mass airflow sensor malfunctioning, misjudging air intake when hot and causing an overly lean fuel mixture. Additionally, ignition coils or spark plugs commonly fail under heat, with weakened spark intensity resulting in poor acceleration. I recommend checking the fuel pump sound yourself first—listen for any unusual noises when the engine is hot, or test the sensor voltage. If that doesn’t help, take it to a professional repair shop promptly to avoid compromising driving safety and wasting more fuel. Remember, this issue is more prone in summer—staying alert can save a lot of trouble.
