So i have JDM B16 with a intake and a catback. Chipped P30 ECU.

All this started to happen since i got my timing belt, water pump, tensioners and coolant flush done.
Recently the car started to fluctuate rpms. Fluctuates when starts itup. From 1500rpms to 2000rpms. Also after the car has been drivin
till optimum driving temp, everytime i clutch in to stop the rpms drop to 100rpms. All the time. Then it would go back to 200 to 400rpms when idle.

Did these procedures:

Cleaning the FITV

Cleaning the IACV

Now the car idles at 1000rpm on a cold start. And drops to about 300-500rpms optimum temp. But the car still drops to 100-200rpms when clutching in.

So I check the ignition timing, it was retarded, but now its a 0. The problem still persists. And I dont get any CELs. So i also decided to jump the ECU, and see if Im running any codes. I dont know if im reading this right, but please correct me if im wrong.

1 solid Engine light
4 quick flashes

Looked it up, turns out its 14 IAC (EACV) - idle air control valve

So looks like im going to replace that. But I also think I should check for vacuum leaks, and do another coolant flush. Also I cant adjust idle with the idle screw because its seized

*Edit Drove the car, start losing power around 7000-7600rpm. Vacuum leak?*

Any input would be greatly appreciated.

Anyone have similar problems? how did you correct it?