What is the normal idle speed for a new car?
2 Answers
The normal idle speed for a new car should generally range between 600-1000 RPM. Excessive engine carbon buildup: This is the most common cause. When fuel combustion is incomplete, or when paraffin and gum residues from gasoline remain, impurities can accumulate in components like fuel injectors and throttle bodies, eventually leading to carbon deposits over time. Ignition system malfunction: When the system operates abnormally, spark plugs are prone to misfiring, which not only increases fuel consumption and reduces power output but also causes irregular idle speed. Engine mount deterioration: As rubber components, engine mounts are highly susceptible to aging and damage. Their vibration-dampening effect on the engine inevitably weakens, resulting in abnormal idle conditions.
I've been working around cars most of my life, fixing all sorts of issues, and when it comes to new cars, normal idle speed usually lands between 700 and 900 RPM for gasoline engines—diesel ones might be a bit lower, like 500 to 800 RPM. Cold starts can push it higher, up around 1200 RPM, but it should settle down once warm. If it feels rough or jumps around, common problems include dirty air filters, clogged fuel injectors, or sensors acting up. New models with electronic controls manage this pretty well, automatically adjusting for things like air conditioning kicking in or transmission demands. I always advise owners to pay attention early; ignoring strange idle noises or vibrations could lead to bigger headaches, like engine stalls or wasted fuel. Checking the battery and basic maintenance every few months keeps things humming smoothly.
