I changed the fuel filter and plugs within the last 5,000 miles.
With a good pressure and adequate flow (which I measured at 500ml in 10 seconds) I am beginning to suspect a sensor/electronic fault. I need to start eliminating possibilities - I have a full on day today but if I have time when I get back I will try injecting a little fuel into the throttle body before starting to see if that additional enrichment helps and go from there.
The issue does seem to be cranking related - once it fires and runs its fine. I’m racking my brain as to what is different about cranking? I read somewhere that the ECU fires the injectors 3 times per revolution on cranking and over 200rpm reverts to one per revln.
As further background I have also cleaned the throttle body, idle air valve, checked for induction leaks, put a meter on the TPS, changed the CTS, changed the CPS and more.