Rough revving between 2000-3000 rpm when cold

[judasentinel]

Is it normal for a GTR to bog and run rough between 2000-3000 rpm when cold, and once you go past that rpm it is smoother?

My car idles fine at 1100 rpm when cold and slowly comes down to 950. But if I rev it, it bogs and runs rough between 2-3K and then continues to rev up.

I had cleaned up the IACV earlier, and no change. I think I should do it again and see how it goes. Other than that, ideas?

[Skym]

That's normal, it's the ECU pulling ignition timing to protect the engine during warmup. It's adjustable if have Nistune installed.

BMW has a rev limiter that raises as the engine warms up and I think Link, ViPEC ECU have this feature.