What is the normal idle speed for a cold engine?

[CaydenLynn]

A cold engine idle speed of 700 to 800 RPM is normal. The reasons for excessively high idle speed are: 1. The idle switch does not close; 2. Faulty idle control valve; 3. Intake pipe leakage; 4. Incorrect valve timing; 5. Fuel injector dripping or clogging; 6. Exhaust system blockage; 7. EGR valve opening during idle conditions. Solutions for excessively high idle speed: 1. Adjust or replace the throttle position sensor; 2. Clean or replace the idle control valve and use a diagnostic tool to perform a basic idle speed setting; 3. Locate the leakage point, reseal or replace the relevant components; 4. Check the timing marks and readjust the valve timing according to standards; 5. Clean and inspect each fuel injector's spray volume to ensure no clogging or dripping; 6. Replace the three-way catalytic converter; 7. Remove carbon deposits from the EGR valve or replace the EGR valve.

[JudahFitz]

When I first started driving, I also found idle speed issues quite complex. But after driving for over a decade, I've figured out some patterns. During cold starts, the idle speed is usually higher, typically between 1200 to 1500 RPM, which is normal as the engine needs to warm up quickly. After waiting a minute or two when the temperature rises, it stabilizes around 800 to 1000 RPM. I've driven many cars - Japanese models generally drop faster while German cars might be slightly slower, all within normal range. If the idle speed stays above 1500 RPM after cold start or suddenly drops below 700 RPM, be cautious - it could indicate a dirty throttle body or faulty temperature sensor. I recommend not rushing to drive after cold starts; wait until the idle stabilizes. This protects the engine and saves some fuel. If you encounter prolonged high idle speed, get it checked at a professional shop immediately to prevent bigger issues.

[DeJourney]

As a new car owner who just got my driver's license, I was initially confused by cold idle speed too. By reading the manual and consulting car-savvy friends, I learned that high idle during cold starts is normal, typically ranging between 1200 to 1400 RPM before gradually dropping to 800-1000 RPM. For instance, my current car shows 1300 RPM upon startup, which decreases to around 900 within minutes. If the idle is unstable or remains excessively high, it might indicate worn spark plugs or a clogged air filter needing simple replacement; too low could mean dirty fuel lines. Winter cold starts often show higher idle speeds, which is beneficial - no need to worry. Now I always glance at the dashboard during startup to spot issues early. Should abnormal idle occur, I immediately schedule maintenance to prevent driving safety risks.

[Haven]

I've always been passionate about automotive technology and have studied idle mechanisms. During cold starts, the idle speed should be higher, around 1200 to 1500 RPM, which is set by the ECU for rapid warm-up. After stabilization, it should drop to 800 to 1000 RPM as normal. If it remains consistently high, there might be an issue with the coolant temperature sensor or intake system. Using an OBD diagnostic tool can help identify and resolve fault codes. Temperature has a significant impact, and it's not unusual for idle speed to be higher below 0°C. Keeping the throttle body clean helps maintain stable idle speeds. Regular checks of the fuel system and ignition coils are recommended to prevent issues.