Here's the situation:

LRD2 with 190K miles, engine rebuild 7 years ago at 125K because of a slipped sleeve (fitted with new "top hat" flanged sleeves), replaced MAF sensor with a new one 3-6 months after the rebuild, used a new Bosch part.

Threw MAF code a year or so back (had that knock sensor coaxial cable fail just before that, fixed it), replaced the MAFwith some 2nd tier sensor (i.e., not Bosch or Delphi -- penny wise, pound foolish, I know). Kept the old Bosch MAF sensor in the storage compartment, just in case.

Threw P0102 (MAF), P0135 (O2), P0155 (O2) about a month ago, but kept clearing codes and driving it.

Week ago, it went into "limp home" like behavior after being driven a few miles: significant hesitation, unwillingness to rev beyond 2000rpm, stalling. Limped back to friend's house, sprayed the old Bosch sensor with some MAF cleaner and swapped it in for the junk sensor, it ran fine all the way home (about 40 miles).

Filled up with gas on the way, it was having trouble filling; stopped a couple of times before getting to full (because of pressure build up in tank, not breathing/venting properly?)

Driven twice since the fill up, at start up it has had no power, won't rev past 2,000rpm until it has been running for a minute or two.

Also, the air injection pump doesn't seem run with high volume vacuum cleaner-like noise level for a minute or two at start like it normally does, though there is some vacuumy/sucking noises from that corner of the engine compartment at speed but can't tell if is that air pump or just the wind on the A-pillar (as I also recently lost the A-pillar trim piece on the passenger side).

Cleared the three (3) codes (those were the only three MIL codes read), but haven't driven it since.

So seems like there might be a couple of things going on here, and before I start throwing parts at it, I'm looking for some advice on how I might approach it, as it could be the MAF, the O2 sensors, the fuel pump, some combination thereof or maybe something else. I can put some fuel pressure gauges to put on the schraeder valve on the injector rail as a start (but can't get to where I store them for a few days). Also, I haven't changed the air filter, and it probably has 50K miles on it (I have a new one, just haven't renewed it yet).

Thanks in advance for any help.