My idle fluctuates up and down at warm up between 1200 and 1700 rpm, wont go
down. Will low coolant level affect idle like ths ?

 

thats whats happening to my d16y8 it idles around there but the temp is normal. I have a bad o2 sensor and no cat so im putting eveything back to see what happens, im not saying this is your problem, but if someones knows it will be sweet.

 

Can't see why unless there is some other problem with the cooling system. Its more likely you have a small vaccum leak somewhere that becomes a problem when the car heats up.