I know this isn't a thirdgen but my friend has a 3.4 94 firebird, he was having issues so we checked his fuel pressure in the book it says 49-55 and it should be 3-10psi lower at idle it was around 40ish. So we slowly increased the rpms and it the pressure stay around 40 then when it his 4000 it drops to 35. What could be the problem a bad regulator or fuel pump?

 

most likely fp. has hhis milage been crappy/lower lately (pin hole in fuel line maybe)? fp supposed to drop when in gear/running due to more injector use.