I have a 2007 V6 Toyota Highlander Auto Transmission with about 115K thousand miles on it. About 4 months ago I noticed that it would have a high ignition RPM after a cold start. At first it was only a maybe a couple hundred high, but now it will hit 1800 almost 2000 RPM on a cold start, does not do it if engine is warm. It does return to a normal idle speed (about 800-1000) RPM, or atleast what I think is normal, after 10-15 seconds of warming up. What could be causing this to happen? It sounds like someone has their foot on the gas for a second and then lets off real quick when the car turns over. Thanks for your help!
Agree with others if your where its been very very cold (0 to 10F in the morning). Throttle body could be a little dirty but nothing critical.
This is totally normal when the cold weather hits.
If you're in really cold climate, I think you're fine since it does drop down to normal idle rpms after 10-15 seconds like you said, but here's a link to some explanations I found on the interweb.
https://www.autopadre.com/blog/why-does-my-car-idle-high-when-i-start-it
