Rb20 idle problem

[xdream]

hey when i start my rb it has a few problems.

1. upon start ( using stock gauge cluster) the rpms go to 2k-2.5k is wrong cause i know the rb idles at 600 rpm. i also know the rpm gauge is wrong but what does that rpm range convert to?

2. also there is an intermittent problem with idle. at random times usually a 10-20 seconds after start the car seems to idle low then goes higher and then continues in this cycle like the IAC is going crazy! what causes that problem?