Flashing Exhuast Dash Light, No Go, R32

[stimps]

Ive read the owners manual, gee its tough in that section, but ive found so many other things wrong and fixed them, but this problem doesnt go away.

What happens is when i start on a cold morning, no problems, it starts and idles fine. Engine check light (or cat converter overtemp light as its properly known as) does not come on. Then i pull out and drive off and as soon as the revs biuld up to 3k or so, and a little boost comes on, this light starts flashing randomly on and off along with the light on the side of the ECU. (I have modified the ECU so I can access and see the light and dial switch on the ECU without removing it. )

I can keep driving, power seems down a bit, response is terrible, with the light flashing, its really annoying of course. but it will still boost and drive ok.

Then I pull over and shut it down, wait a second or two, restart (now with a warm engine) and it goes fine. No issues and heaps of power and response as it should.

Any clues anyone?

Really hoping to bump into some sort of Nissan R32 Guru on here to pick his brains!

cheers thanks for your time