I don't think you can with stock ECU unless you have some sort of diagnostic tool. And you're right, cold idle is usually higher.
You mentioned you changed your coolant temp sensor recently right?
Yup it was changed. Also there are change in the temperature meter when car warms up. Im thinking...maybe i should clean the throttle body first. Will spray one can of throttle body cleaner into it tonight.
I'll be letting go of my pride & joy for something new to work on
.. Yes the southern 300bhp 1zz MRS is for sale.. specs of the ride as below;-