Weird Cooling system Prob after S14 SR swap. Overheating with Koyo

[DUBCITY]

So im finishing up my kouki s14 sr swap, but im having major difficulties with the cooling system.

I have a koyo all aluminum radiator, and for now im only running the clutch fan and no shroud. Coolant is new and all air bubble have been removed from the system from the bleeder and parking on a slight incline.

When i start the car up it warms up just like normal. If i pull the rad cap i see the water rushing by so i know its circluating (pump and thermostat are good). My problem is that if i let it idle for about 5 min after reaching operating tempurature, the temp starts to rise and the Koyo rad gets so hot it will burn your hand. If i pull the cap when its this hot, it doesnt do anything erratic, all i see the the coolant rushing by like it should, but the temp is still above 1/2 way.

Then if i take the car out on the road and drive around, the temp drops back to where it should be, but the weirdest thing of all is that when i give it full throttle, i see my temp gauge shoot up really fast and then back down all in a matter of about 2 seconds. Ive never seen any car ever do this, anyone else have a crazy temp problem like this?

And then if i bring the car back in and let it idle it will heat back up just like before.

Any help would be great since im sitting here with my thumb up my ass wondering what my next move should be.