Idle fluctuation is a common issue in Honda Civics. The rev counter moves up and down while idling, making driving uncomfortable and increasing fuel consumption.

Symptoms

• Sudden RPM changes at idle
• Engine stalling
• Increased fuel consumption
• Vibrations at idle

Possible Causes

• Dirty/faulty throttle body
• Idle air control valve (IACV) malfunction
• Vacuum hose leaks
• Dirty fuel injectors
• Faulty spark plugs or coils

Solutions

• Clean throttle body
• Inspect/replace IACV
• Check for vacuum leaks
• Clean injectors
• Replace spark plugs/coils

Advice

Fixing early reduces fuel costs and prevents breakdowns.