If its idling at near 2k though tabetha then trying to set his CO will be a nightmare. Ive found adjusting the CO at idle from both extremes only effects the idle a relativly small amount when on standard cams (except when adjusting so far that it starts to hunt). If it was idling at around 1000 then yeah I'd say check the co first. To be honest I have mine idling at 1000 anyhows....Ive found it makes such a difference to the oil pressure when compared to 900.