My Civic idles bad in neutral- Please help!
 

My 2005 Civic with a 4 speed automatic transmission normally idles at about 1,200 RPM in neutral while sitting still, but started this weird thing of idling at around 2,000 RPM while coasting in neutral and the idle drops as I slow down. It is not the idle air control valve, since I disabled it and it did the same thing. The other thing that I noticed is that if I jack up the front of the car and start it in neutral, the wheels spin almost as fast as if it is in D4. I think the transmission is not disengaging the engine from the wheels fully when in neutral, and the wheels are spinning the engine when coasting in neutral. Does that sound reasonable? Thanks in advance for the help!

Have you disconnected the battery recently?

7th Gen Civics have an idle learning procedure that they need to go through to reset the idle any time the battery is disconnected.

I wouldn't worry about the wheels spinning in neutral unless it is enough to move the car when it is on the ground.

A little late here, but even 1200 rpm sounds too high. Rev the car up by hand and see if you can push the throttle back even more than what the return spring will do. This sounds like a sticky throttle cable.

Did they still have a throttle cable in 2004?

Yep.

Yes, I checked the throttle cable. The tension is correct.