Poor mileage and running rich

[Clint09]

keyon pressure is 36 and drops to 30psi on mine,

43 is max no matter what.
what matters most is the 6 PSI change from keyon to idle.
that matters big time if you go to full throttle the PSI will to down to near keyon pressure  as low as 30

why is your pressure so high?
is the return line partially blocked/ or pinched, but what matters first is the 6PSI above,

good report  so far, you have handle on what was done and what might be wrong still.

Not sure me if this year has limphome for P04xx codes, I do think not, but.... nobody knows all ECU that well.

I rechecked fuel pressure it’s at 42psi with key on and 35psi at idle. I took the entire return side of the fuel system apart and could blow air through it so that’s not restricted. I put about 40 miles on it with the o2 unplugged and it still runs super rich at idle possibly even worse than before. Just got done running a NOID llight test on the injector wiring connectors and they all blink and seem to be working normal. Also I forgot to add that when I started trying to figure out this issue about 6 months ago the EGR passages were plugged and the intake manifold was caked with black sludge inside so I took it off and ran it through a parts washer until it was spotless inside. I noticed today looking through the throttle body that it is starting to build up black grime inside it again.