idle issues go away with heat on

What the title says.
It seems like my idle issues go away when I put my heat on, my idle isn’t bad, but it seems that when my engine gets to OT it will drop idle a little bit, but if I put my heat on after about 20-30 seconds its seems to idle perfect. Thinking something in the cooling system, any ideas are welcome. I Havnt cleaned my iacv ever, or messed with the fitv, but my mind theory (lol) it wouldn’t make sence to me that it would be the iacv, as it goes away with my heat on, and not positive if it does the same thing with the temp turned to cold.
Stock b18a1 only mod on engine is the CAI, Bosch plug wires ngk iridium or platinum, can’t remember unless there the same haha, and brand new rpt distributor.
Any help is greatly appreciated
Thanks in advance

try to clean your IACV first…seems more like a IACV issue to me…but u can clean your FITV as well

Thanks man, I’ll try that, just didn’t seem like it wouldn’t be either just cause, to me anyway I would think it would mess with my idle more because of the extra load of electrical from the heater.

there’s usually a load from running the a/c not enough from the heat, because if i’m thinking correctly, heat from the engine is being brought in, the only thing really running is the fan to blow it inside the car