2000 Civic LX was in a small fender bender and sat awhile before repair. It was running great when parked, but after repairs was presenting a "loping" idle after starting and initial warm up. I replaced the IAC valve and now it runs smoother but is very high idle. I tried to adjust cable, but no difference as the throttle cable is fully extended. Is there another adjustment for idle, or is something else the problem?

 

try to let it relearn. Pull ecu n backup fuse for a few minutes to clear the ecu n then start the car and let it idle for around 5 minutes without touching the gas.

 

there should be a high idle adjustment screw at top or bottom of throttle body. I cant remember as Ive had an aftermarket TB for too long..lol

 

It will throw a CEL code eventually P0505 for engine idle speed.

You probably have a vacuum leak. Start it up and open the hood and listen for air leaking in. There are some really crappy intake manifold gaskets on the market now and it might be that. Also, might be a vacuum hose is popped off, like the cruise control vacuum line at the back of the plenum.

If you determine the problem is not a vacuum leak, then adjust the idle speed screw.

 

Try the idle adjust in the FAQ