Why did the “Check Engine” light come on after refuelling and now engine idles rough?

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Why did the “Check Engine” light come on after refuelling and now engine idles rough?

I noticed that soon after filling up at a petrol station, the EVAP purge control valve or associated EVAP system might have gone wrong — right after the refill the “Check Engine” light popped up on the dashboard and since then the engine idles roughly o r sometimes stalls at idle. Could a faulty o r stuck‑open purge valve be the cause? What exactly goes wrong inside the EVAP system to cause rough idle o r stalling after refuelling o r during idle in Tiggo 8 Pro?

Talha Kyanii asked on 06 Dec 2025 10:16:25 am

1 Answer

7 views |

Gari Master - on 06 Dec 2025 10:17:37 am

A rough idle after refuelling combined with a Check Engine light often points to a stuck o r faulty EVAP purge control valve. Possible causes:

Stuck open purge valve: Allows excessive fuel vapors to enter the intake manifold continuously, leaning out the air-fuel mixture at idle and causing rough idle o r stalling.

Stuck closed purge valve: Prevents proper venting of fuel vapors, potentially increasing fuel tank pressure and triggering EVAP-related codes.

Vacuum leaks in EVAP hoses o r connections: Can mimic purge valve problems and contribute to rough idle.

Action:

Use an OBD2 scanner to read the exact EVAP-related code.

Inspect the purge valve and hoses for damage o r blockages.

Replace the valve if it does not open o r close properly.