Thanks for the reply Kim
I had another look today, and with vehicle stone cold from over night, I found a very small leak when I smoked the exhaust again.
Previous tested this when warm and no leak from joint
This leak was at the cat to down pipe flange just before the down stream O2 sensor. resealed the joint, reset all learned values, after a extended test drive the P0171 was back
STFT was +9% switching to 0% at idle.
I will do a fuel pressure test and injector voltage and amp measure in the morning.
Thanks again for the input