Need idle expertise

Ok here is my situation... I have an 02 with Hard Chrome exhaust and a K&N football filter. I cant get it to idle constant and rpm's slowly go down until it dies. Once it reaches operating temp it will remain at idle for a little longer before declining till dead. It doesnt miss or sound weird but just falls down to under 600 rpms then its dead. I have tried pilot jet sizes 27.5 32.5 and 37.5 and the outcome is the same. Here is where it gets even stranger, if I lean it out to only 1 to 1.5 turns out on the air/fuel mix screw it will actually idle for me but 2 things happen to me..... after riding around for a while and stop at a light it will idle upwards of 1300 rpm then gradually go back to the 1150 I have it set at. I know its lean doing that so thats where I need some input as to what to try next.
I also assumed vacuum leak so I changed all the lines with brand new and even changed the fuel lines. Also had another fuel pump and ignition module....nothing changed.
Tried going back to stock with airbox and jets and you guessed it...same thing