Sorry I did not read before now that you had this problem Richard but it is an easy adjustment
@pete.triumph and
@CanberraR3
On the Test screen of TuneECU the second last test down the left side is "Adjust ISCV" double click this and follow the instructions (along bottom of screen) to do this as it will help you check and set TPS and Stepper motor adjustments.
I only recently had to redo mine I have found every so often possibly due to vibration on a long run, one or the other may slip a tad and when doing the procedure repeat it a couple of time as it is only a minor movement to make it a minor change and that is all it takes for the system to play up,
Hope this helps you guys
PS I will have Laptop and cable with me At RDU if anybody else needs to do this