Evening Mark,

Bit of a poser this one. Fuel pressure looks good and O2 is good. Like Mark, do not understand the MAF readings. If there are no air leaks in the breathing system etc then I would like to scope the MAF. Is it possible that the HO2 sensor is glitching?

I had something similar with a BMW a couple of weeks back and after resetting the DTC, I could sit and watch the graph of the STFT slowing rising until it reached the 25 point. already searched for an air leak but convinced that there was something still there, I pulled at every crankcase ventilation pipe I could find and one actually came away in my hand. It was not connected properly and it was the suction of the inlet manifold that kept it in place.

Maybe a long shot but worth another look.

Best of luck

Pete M