Big difference between .3 and .4 differential pressure. ( Assuming you set it at .4. Could you CONFIRM the differential pressure now that is running better?)

From a cold start, does it rev @ ~1100 rpm for 28 seconds then settle in at ~800 rpm.

If it were me, I would go and set the mixture using the X11 port now.

__________________
1993 2.6 Sportline 5 speed
1992 2.3 Canadian delivery