More bloody problems!

[Niall]

I wouldn't waste any time getting a replacement ECU mate, it's money you could put towards basic aftermarket management.

The trouble is, that with the GTi6 inlet and exhaust manifolds and other changes the sensors are reading outside various parameters that they normally would, so chances are a new ECU would just have a 'temporary' lifespan on that engine, before confusing itself. Part of the reason I returned my Cabriolet back to standard manifolds (although in hindsight, I wouldn't have bothered putting the exhaust back to standard as this doesn't seem to affect the car at all). The new TB from a GTi6 has to be maybe 50% bigger than the standard one, so your letting in a whole lot more air. Not to mention that the ambient air mass inside a GTi6 inlet manifold far outweighs what should be in there, with the crappy restrictive plastic one...

In your position, again, I would source an aftermarket ECU (can you get a megasquirt one?) and GTi6 cyilnder head. Get it mapped and have done with it.

Yep but that requires lots of money which is something I just don't have at the moment.
I'm going to try a new lambda I have laying around and if that doesn't cure it, it has to be the ECU. It can't be anything else. Ecus on these are known for doing this.
Might swap back to the 1.8 manifold anyway soon but we will see

Oh and I'm not fitting a gti head. I've just fitted a newly refurbished one!