1986 Ford LTD wagon 3.8 TBI - not running right

[FTWalker]

~82K miles. Same vehiccle as in the other thread of mine. Ran decent until about 3 weeks ago.
Problem started overnight - literally.
Idles rough, drives rough, and fells like it occasionally wants to cut out under moderate acceleration. Fuel milage was kinda crappy before, and still is (350+ miles per tank when the car was younger, now it's lucky to break 200 since it's came out of retirement)
Plugs are new, wires & cap appear solid, fuel filter's new. Checked the fuel pressure - 38PSI and steady under idle. Vacuum lines appear good and seat firmly.
I don't remember the exact codes, but they translated as:
1)EGR position sensor out of range
2)system lean
3)right O2 sensor lean
Those were the -only- codes, from a quality Snap-On handheld unit.
Pos. sensor replaced w/ new, comp. cleared to re-learn - no change in symptoms or codes.
EGR cleaned thoroughly - as above.
EGR replaced w/ one from a local parts yard, used the new sensor, comp. reset - no change in symptoms, but haven't checked for codes yet.
I'm guessing that I'll have to break down and change the O2 sensors (the symptoms are a good fit), but I'm open to (and hoping for ) something else to try.
Thanks in advance!!

[Tuffdrvr88]

Have you checked your fuel pressure regulator? You could also try cleaning your fuel system with some "sea foam" through the pcv valve. Hope that helps, good luck.

[FTWalker]

Haven't checked the regulator yet, since the fuel pressure readings I was getting at the throttle body appeared rock-solid and steady. Haven't done Seafoam through the PCV, but I have ran 2 cans through the tank. No noticable improvement.
What I did do that helped some was changing the distributor cap & rotor. Plug wires are next when I get some time. I decided on this when I saw that it ran worse during damp/wet weather. I guess that looks aren't everything.