Repair Procedures: Cleaning

WARNING: This page is about a different car, the 2017 Kia Optima. However, it is still accessible from the selected car via links, so may be relevant.

The combustion temporarily becomes unstable, due to the aged fuel and the carbon deposits accumulated on the spark plug(s) after long-term storage.

[1st Method]

Start the engine and keep the engine running at idle for 2 minutes.
Step on the accelerator pedal and hold it steady at 4500 RPM with the shift lever in N position to warm up the engine until the temperature of the engine coolant reaches 80°C.
Keep the engine running at 2500 - 3000 RPM in the N position for 15 minutes.

Courtesy of KIA MOTORS AMERICA, INC.

[2nd Method]

NOTE: The 2nd method should be performed only if the 1st method fails (the misfire-related codes recur).

Start the engine and keep the engine running at idle for 2 minutes.
Drive the vehicle for over 20 minutes, keeping the engine speed above 3500 RPM.
NOTE: If equipped with manual transaxle, shift the gear properly for keeping the engine speed above 3500 RPM.

Courtesy of KIA MOTORS AMERICA, INC.