did my TDI / AFN conversion last year , and ever since i have done it i have always had this problem , basically i dont have any power after starting up ,
it wont rev 1500/2000rpm max... untill i hold my foot down for 2-3 seconds , then it revs 3000rpm + , then its fine , runs fine , revs fine..
now turn ignition off , it happens again . so it is defo ECU related.
no fault codes
i have all my brake/clutch switches that come on donor car taped closed ( is that a problem ? , never got around to mounting them on pedals yet ? )
so its like the car is in limp home mode , or maybe something like cruise control is cutting in and trying to slow engine down ? but reving it hard overrides it ?
did try lots of things months ago .. but left it .. as i just rev it everytime

regards
Matt