What are the reasons for high idle speed in winter that does not decrease even after the car warms up?

[LenaDella]

Winter car idle speed high does not decrease even after the car warms up reasons are: 1. Oil accumulation in the throttle and excessive carbon deposits on the throttle; 2. Weak spark due to spark plug failure; 3. Fuel line blockage, intake pipe failure; 4. Sensor failure causing the ECU to lose control; 5. Fuse blown, ignition module failure; 6. Low fuel quality. The methods to address high engine idle speed are: 1. Clean or replace the idle control valve and use a dedicated decoder for basic idle speed setting; 2. Locate the leak, reseal or replace related components; 3. Adjust or replace the throttle position sensor; 4. Clean and inspect the fuel injection volume of each injector to ensure no blockage or leakage; 5. Remove carbon deposits on the EGR valve or replace the EGR valve.