fuel pressure regulator

[EEYORE5182@aol.com]

it was brought to my attention that my bad gas mileage could be caused by a
faulty fuel pressure regulator.  when i think about it, i guess it makes
sense.  when i think about it though, i guess i think that a fuel pressure
regulator is an aftermarket part, since people talk about getting them.  i
would assume every car that's fuel injected would have some sort of piece
that would regulate the pressure of the fuel.  so now i want to check mine.
is there any way to tell that its bad? should i replace it with an
aftermarket one?  how does the thing work anyway?  im pretty sure that once i
know what to look for i can replace it.  this gas mileage thing is really
getting out of hand.  im thinking the car is running so rich that its
actually robbing some horses.  i have already put in new plugs, changed the
wires, etc.  and i recently got the hotshot header, a catco cat, and the
courtesy midpipe.  i had low dyno #'s when i tested it w/just the CAI, POP
and rear muffler section.  i did have my 16's on and i found an obsturction
in my factory midpipe when i cut it out, but still 119 to the wheels...that
sould have been a little higher i think.

any of this make sense, or am i rambling?

Alex
'93 NX2k