Just started my motor coming from winter hibernation. Idled normal for a few mins, increase the throttle and wouldn't return to 800 RPM - sits up at 1500. TB is closed, all vacuum lines are connected. Timing confirmed - same goes for all sensors. Temp sensor reading correctly, No codes

Any thoughts?

If convinced not vacuum leak or tbody blades hung open s tad, could be stuck IAC (idle air control valve.)

Seems to be the problem, replaced an IAC with a new one last season chasing an issue that turned pout to be the distributor. Swapped the original back and it idles at 800 again!

TY