Hey guys, anyone, anyone at all got an idea on this, been driving me nuts for ages now, nothing seems to be obvious...

Warm car up for a minute, drive off, nice and gentle for 10 mins or so, engine temp comes up quick as I have new thermostat, g/box is freshly rebuilt and running sweet, car itself runs sweet, but if you try to accelerate too hard before the car has been driving at least 30mins, it cuts out violently on acceleration, usually around the 3500-4500rpm mark, like someone is turning the ignition on and off, or the ASC valve is closing and opening rapidly. Once really hot no issues.

I thought it might be the CA sensor at first, it was new a couple of years ago, genuine, swapped it over and no difference so swapped it back. Measured the temp sensor next to the temp sender and it was in manual spec cold, no mechanic has ever come across this and its definitely no good for the car, puts huge stress on everything if I suddenly need to boot it and cant because it starts cutting out.