Hard Idle When the AC is Off

I have a 2004 Chevy Cavalier. I am having some issues with it.

When it first starts it idles really hard. The RPMs are up and if will try to accelerate without hitting the gas. This stops after the first minute.

The second part is that when stopped, but in drive, it idles hard. It does it though when the AC is turned off. You can see the RPM gauge go above and below the normal 500 RPM. If you turn the AC on then it levels out. It will occasionally idle hard with the AC on, but rarely and not as much.

The car drives well and is not overheating.

Any thoughts?

When you say “idle hard”, do you mean that it’s idling high? Clarify a little bit please, not sure what you mean.

Start by cleaning the IAC valve and the throttle body.

Not entirely clear what you mean by “idles hard”, but if it is idling too fast, that is often caused by air getting into the engine that isn’t supposed to be. Either the throttle plate is sticking open slightly or there’s a vacuum leak. Also , if you have a rubber boot-like thing between the air filter and the throttle body/intake manifold, check to make sure it is connected air tight on both ends, and fully intact.

One other thing that can cause high idle rpm is a problem with the coolant temperature. Check the function of the thermostat and the ECM’s coolant temperature sensor.

All the routine engine maintenance is up to date, right?