chicomacattack

When i turn my ap1 on. Rpms jump to 3000 and then just goes down super low like 400 rpms.

Shaney

I'm pretty new to the S2000 but I'll try to help. Is it cold or does it happen only on a cold start or every start? It may be your IAC valve sticking a little bit when you start it up?

zeroptzero

Do an idle learn procedure. Simple first step before touching anything.

street_ruler

what is an "idle learn" procedure/ ive never even heard of this

zeroptzero

You basically get the car warm, then disconnect the battery or pull the ecu reset fuse for about 30 seconds. Reconnect the battery or reinstall the fuse. Make sure all electrical accessories are off (no heater fan, no radio, no lights, etc.) , if you have drl's engage the e-brake. Start the engine and don't touch the accelerator, let it idle until the cooling fans engage a couple of times, then shut off the engine. That should be it. Hopefully the ecu learns what idle speed is needed and controls the IAC properly from that point onwards.

chicomacattack

It was that. I cleaned out the iac the day before.

Habitforming

That sort of info can be very helpful in the initial post...

street_ruler

i should do this. never did it after the intake install. idle kinda "hangs" from time to time