if im sitting at the lights after a good raz the engine goes to 2500 rpm once ot twice and then back to idle normally. sometines it might be for 5 to 10 seconds
Could be idle control valve or a maf i have a idel valve there for a 99 type r you can try if it fits
Or just pop it off and clean refit and see what up.
Got it in the uk its used all the people i talked to said they never give trouble so i went for a used one think it was 30 quid if it fitss your welcome to try it.