Why is my idle high?
 

I have a 1993 HOnda Accord lx coupe.
When I turn my car on in the morning to go to work, my idle is usually at 2000RPM. Once the engine has been running and I stop, it's back at 600-700 and isn't rough at all. Why is this?

The higher idle is to warm up the engine and emission control components quickly. Normally it only lasts a minute or so.

hondas have 2 valves to control idle. one while the engine is warm and one while the engine is cold.

when the one that controls the cold idle wears out it lets the idle creep. the good news is you can just tighten it. the bad news is i dont know how it works on accords, but people on honda tech do. i wouldnt think it would be too different from civics...

the bottom line is this link might help:
https://www.honda-tech.com/zerothread?id=1003988

Well It's functioning properly then. It does go away as soon as the engine is warm, so after a couple minutes.

you could put in a engine block heater so it goes away even faster and it could get you better fe.

I may do this for winter.

How much is an engine block heater. How long does such a device take to heat up an engine? and how difficult and time consuming is this to install. Im thinking this might be a useful mod before the winter.
Im very curious.

My father is driving an old Mercedes Benz Diesel, and we live in NH (cold in winter!). WHen he gets up and leaves at 6AM, he could never get it started on a cold morning without the block heater to help. He has it on a timer so that it turns on 30-60 minutes before he leaves, and it starts right away. So I think 30 minutes is all it takes.
There's a whole variety of these heaters available, some are easier than others to install.