How to Solve the Idle Vibration When the AC is On in a Civic?

[Bella]

Dirty throttle body or excessive carbon buildup in the fuel injectors. Clean the fuel system and check if the idle control valve has carbon deposits that need cleaning. Check the condition of the spark plugs, high-voltage wires, and ignition coils. Inspect if the spark plugs have excessive carbon buildup and replace them if necessary. It is recommended to visit a 4S shop to check the fuel supply pressure and whether the intake pressure sensor is functioning normally. Inspect the fuel pressure and replace components if needed. Car vibration can also be related to aging engine mounts. If there are issues with the engine mounts, they need to be replaced.

[EmilianoMarie]

I experienced idle vibration when running the AC in my Civic, which is mostly caused by carbon buildup in the throttle body. The engine already has limited output at idle, and when the AC compressor kicks in, the additional load makes the engine unstable. A dirty throttle body leads to uneven air intake, making the vibration more noticeable.

Here's my DIY suggestion: Start the car without AC to check idle stability, then observe RPM changes after turning on the AC. If vibration worsens, try spraying throttle body cleaner. Alternatively, worn spark plugs or faulty ignition coil connections could be culprits - Civic's ignition system typically needs maintenance every 30,000 km.

For accurate diagnosis, visit a professional shop to scan for trouble codes. Throttle cleaning solves about 80% of such cases. Preventive tips: Avoid prolonged idling with AC on, and change air filters regularly to reduce carbon buildup and improve engine responsiveness.

[OLilah]

Haha, I also drive a Civic. When the AC is on, the idle shakes badly, usually due to a dirty throttle body or faulty spark plugs. The AC compressor consumes a lot of power, and the engine can't handle the idle load, causing it to shake. Simple solution: Check the spark plugs yourself—if they're cracked or blackened, replace them. For the throttle body, try cleaning it with a cleaner. At a repair shop, they can quickly diagnose the issue by checking the RPM curve with a computer. The Civic's idle control is a bit sensitive, so regular minor maintenance can save you trouble. Avoid idling with the AC on at intersections—turn it off while waiting at lights. Engine health is crucial; regular cleaning can extend its lifespan and improve fuel efficiency.

[VanEmery]

Idling with the AC on causes annoying vibrations, a common issue for many Civic owners. The main culprits are dirty throttle bodies or aging spark plugs, leading to uneven ignition. When the AC adds load, insufficient fuel supply causes the engine to shake. Inspection sequence: First, replace the spark plugs; if that doesn't work, clean the throttle body carbon buildup; finally, check the idle control valve. Professional shops can diagnose and optimize ECU parameters. Don't skip maintenance—regular part replacements prevent vibrations.