I've got to think a bit or research why the ECU keeps setting my idle at 2k when the car is moving. I get something similar to what you see but only when moving. I can get rid of the surge by raising the Coasting Fuel Cut rpm above what it idles at, but that doesn't fix the root of the problem. I've been putting this off for a long time
The EVO doesn't like the 2g ECU too much, or vice versa. Perhaps in my efforts I'll come across something that applies to your situation. I know the idle system pretty well on these cars, but not well enough I guess