Fuel pressure too high and eradic

Just some background: 1998 Sport 4.0 Auto
-surging on road intermittently, low rough idle sputtering, NO power in low rpm
-if given little throttle under the hood will dog down and stay that way but not conk out
-CEL gave 3 codes, high voltage on both oxygen sensors, and bad O2 heater
-replaced oxygen sensors and CEL was still on, throwing same 3 codes, problems still there
-replaced 15A heater fuse under hood and CEL went out
-still have surging on road intermittently, low rough idle sputtering, NO power low rpm but CEL is gone
-sprayed TB cleaner (TB is very clean though) and idled OK for all of 20 seconds then went back to crappy idle



SO, I bought a fuel pressure checking gauge at Advance Auto and I think its the regulator. Here's what I got:
Cold prime - 48psi - 2psi/10sec bleed down
Cold running - 48-52psi - normal high idle
Cold running - 42-58psi - bouncing
2000 RPM - 50psi - steady
5 min, 190*F - 38-62psi - bouncing, rough idle begins
8 min, 210*F - 36-64psi - bouncing, rough idle

So something definitely isn't right as Chiltons states pressure should be 31psi at idle. The in tank module contains the filter, regulator, pump, sending unit and screen. I'm thinking I might as well replace the whole thing since I've got 145k on this thing and its probably original. Thoughts?

a '98 should be running 41psi-idle, to 49psi at "full blast". o2 sensors won't have any real effect on fuel pressure. sounds like a bad regulator. on some of the later models, the fuel filter/pressure regulator is one assembly on top of the in-tank assembly. and it IS available by itself, though you may have to go to the dealer and they're not cheap.