Thanks Mate, this is what I thought but wanted to check as im having dramas at about that RPM.
I've put a 5.0l in my XF and used a NF fairlane as a donor car. I've got one of your chips to disable smart lock and to change the ECU bin to a manual. The engine is in and running but it has a issue around 3500 to 4000 rpm where it sounds like there is a rev limit of some sort. Even is you hole it flat in neutral it wont rev past this point.
I've tried every v8 manual bin on your site and it's the same with all of them. I've tried different ECU's and still the same.
I've tried 5 different MAF sensors and some make it idle much better and the throttle response heaps better and worse but the rev limit issue is still there.
The engine is mostly stock and It was running in another car perfect with a carb on it. It's GT40 heads and very small cam with a edlebrock manifold. Stock injectors and stock everything else. And the engine was running perfect when it was efi in the fairlane.
Any ideas im kind of stuck and nearly ready to just go Haltech.