Thanks heaps Duncan.
Every bit of info helps. I noticed it was doing the same thing even when it was stock with standard air filter, cars only done 58000kms and it looks genuine.
I,ve done a few tests cheked fuel flow at 3000 rpm and it was 2.1 litres per minute, mixtures seem to be a bit lean at light throttle but ok at full throttle.
I've removed and cleaned air flow meter (not keen on pulling it apart until i've got another one to test with, but my mate has one I can test with so will do that on the weekend) if it still does same thing then I think you might be right about the ECU.
If that's the case Ill get a HKS fuel cut defender or source another ECU as you suggest.
Would the R33 gtst ECU be the same as the Stagea, also my Stagea is a manual so obviously I would have to go for a manual computer but I have heard that you can use Auto ECUs on manual cars, mine is the RB25 Neo motor. Is there any other ECUs that will do the job??
Another mate of mine also suggested throttle position sensor can also cause same problem, but if it was the throttle position sensor I would have thought it would have only done it on light throttle not through to full throttle??
But now that you say that it richens the mixture that makes sense to me as when I first got the car I was getting 550 km per tank and even 600km out on the open highway. Now I'm getting around 480km per tank and it seems to be doing it worse now than when I first got the car.
I'm at a bit of a loss, but I think I will just have to use the process of elimination.
If you can think of anything else that it might be please let me know.
Cheers