For a few months i've constantly had a check engine light with the code P0171, to fix this I sealed a vacuum leak and replaced the fuel filter to no avail, i'm aware of a fuel pressure regulator recall

Interesting, do you have the GM Recall # or the TSB for the fuel pressure regulator?
An experienced shop with a good scanner can also look at live data & help to diagnose the code/* more effectively.
This site makes some interesting recommendations:https://www.autocodes.com/p0171_buick.html

If you don't know how old the current fuel pressure regulator is, replace it. A bad one can make your car annoying and/or make it burn to the ground.

Also, check fuel pressure, key on engine stopped, at idle, and at idle with vacuum disconnected from fuel pressure regulator.