Rb25det Neo No Power Rough Idle Only When Warm.

[theDETlife]

R34 gtt neo engine replanted into r32 gts body.
recently the car has been running fine until it gets up to temp, then when driving normally its fine won't miss a beat.
as zoo as you give it a tickle on boost after coming off boost it starts to give in. No power, rough idle, you can smell its running rich. Any position on the accelerator will not have an effect on the rev's when in neutral or in gear, a slight change in rpm but it will still continue to run terrible. will not rev past 3k, but sometimes will not rev at all it vary's a lot.
There are no vacuum leaks that I'm aware of, gauge reads a constant 20 vacuum at idle.
can anyone suggest how i go about ruling out this problem step by step. which areas do i cover first to see what is at the heart of the problem.

Cheers have a fine one.