Yesterday when I start my Evo (05 GSR, mods in sig) it will rev up to 2k then settle down to it's normal idle routine. It is almost like what the car does after you reset the ECU, just that the ECU is not resetting. I can't figure it out.

Like I said it only does it at start up and it will go back down to the normal 1100 rpm warm up then down to 850 or so once it's warmed up. Just kind of strange for it to start doing this out of the blue. It also will do it even if the car is still warm and it appears to be intermittent. It does not do it everytime. I was wondering if I should be worried or just live with it.

I have not tried resetting the ECU yet.

 

my guess is that your idle control valve is initially sticking open. You may want to remove it (it's below the throttle body and held in by 3 bolts) and clean it with carb cleaner also cleaning where it seats inside the throttle body. Don't drop it BTW it retails for $330. If you're still under warranty take it in and let the dealer do it