Ive just fitted a scorpio engine in my sierra with rs2k ecu and injectors but its idling to high, using scorpio manifold and throttle body, whats the best way to adjust it? If i can?

 

It's likely to be controlled electronically so via the ISCV, I doubt if these have a mechanical base idle that you can adjust. Unplug the ISCV and see if the revs drop, other than that there may be an air leak.

Martin