I have a 1998 Civic DX which is completly stock for the records lol. Here is the problem

Car starts fine and runs fine.

When you start the car cold it goes through cold idle and then once warm is at 750rpm and idles great

If I drive it anywhere after it has been warmed up and restarted (say, Leaving the store after shopping) When you turn the car on and touch the gas it will idle between 3000-4000 RPM.

Again it only does this after restarting the car after driving.

It does have a CEL for secondary o2 sensor but it has been on for 7 years we have owned the car. and has never affected the way it runs besides gas milage a bit.

Any Ideas?

 

Clean the IACV and throttle body.

Also adjust the throttle cable to have some slack (see service manual).

 

Ok that was my plan over the weekend anyways. Just wanted some other input on what it could be or if anyone else has had common symptoms

Thanks