Running rich badly!

[Flybiyou]

So I installed a Walbro 255hp and at the same time installed Aeromotive FPR . I set base at 43 psi and it sits at 34 psi at idle. Every since I installed these I got a cel for running rich and I am badly. I'm getting 220 miles to a tank with some playing of course but I had 1 of these years back same setup and this never happened. I remember there being a mod to the return line at the housing but if I remember right that was for 2g AWD only. I did replace the TPS Orings and fixed every boost leak I could find. Replaced all the Orings on the Injectors. Since this I have also noticed that I'm not boosting over 10 psi at wot. It peaks at 16 then drops to 10psi and holds through the pull. If I let up on the throttle some and hammer down again it again peaks to 16 psi for a sec and drops to 10psi again.

Any ideas? 97 gst stock except 3" cat back / filter / bov recirculating/ front mount / fuel pump and fpr / manual boost controller. All emissions removed block off egr plate.