Idle Speed
Idle speed is the engine speed when the car is stationary and the accelerator is not pressed.
What is Idle Speed?
A warm petrol engine typically idles at about 600 to 900 rpm. It is higher when cold or with the air conditioning on. The engine control unit regulates it. Diesels and large engines often idle slower; hybrids and start-stop cars switch the engine off at idle.
How it works
The control unit adjusts the throttle or idle valve and timing to keep the target speed.
Why it matters for your car
Unstable or high idle points to air leaks, dirty throttle or sensor faults. Idle relearn may be needed after cleaning the throttle.
Other terms
- AdBlue Heater
- AdBlue Warning Light
- Balloon Payment
- Barn Find
- Brake Judder (Brake Vibration)
- Clear Coat Failure (Lacquer Peel)
- Clutch Release Bearing
- CNG (Compressed Natural Gas)
- Duty Cycle
- Load Index
- Naturally Aspirated Engine
- Off-Road Vehicle (4×4)
- Permitted Axle Load
- Piston Ring
- Public Charging
- Sensor Ground (Signal Ground)
- Steering Angle Sensor
- Strut Brace (Strut Tower Bar)
- Torsion Beam Rear Axle (Twist Beam)
- Wheel Hub