Fuel supply issues (problems ?)

[Pcarselle <pcarselle@worldnet.att.net>]

Audinats and contributors... need advice:
Have an 1987 5000 CSTQ with 162K. miles. In very good shape.
Recently , the normal (but fairly loud) buzzing noise from the fuel pump
has intermittently increased in level to about double the intensity with
the following consequences:
When the buzzing gets louder ( every 20 minites or so )
1.- The car misses when subject to acceleration. (all gears)
2.- The tachometer indicates the engine  is substantially slower (about
twice the time) to return to idle or to decrease RPM's to a good shift
range.
3.- Engine idles fine even when increased pump noise is present.
4.- Turning ingnition off and restarting makes the buzzing noise go back
to normal.
5.- Abnormal buzzing seems to occur more frequently with a full tank.
Actions to date:
Replaced Fuel filter
Added fuel de-icer/water remover (one time)
Filled tank....problem frequency increased
Pulled "output" codes with following results ( I can't understand )
1st code - 4433 ???
2nd code - 4441 ???
3rd code - 4442 ???
4th code - 4443 Cold start valve
5th code - 4343 Carbon canister shut-off
I have not been able to decode or understand the first 3 codes.
Suspect:
Fuel pump strainer clogged
Check Valve
Pressure accumulator
Control pressure regulator.
Any advice/guidance will be appreciated...
TIA.
Pablo