I have stock tbi's. I had to rebuild the fuel pressure regulator. the manual says they are calibrated and plugged at the factory. however, when I tore them down to replace the diaphragms and gaskets the inner part screws in/out which leaves me to believe that I am lowering or increasing pressure if the screw is moved. it is almost impossible to take it apart without moving this screw. any advise about the fuel pressure regulator anyone can give me so that it delivers the normal stock pressure when I put back together? any info will be greatly appreciated. thanks in advance.

 

IIRC the inner part screws in and out but you could have removed it without changing the setting. Try to put it back at the same height it was when you removed it.