Buy a fuel pressure regulator and a Torx tamper-proof bit set.

Remove the engine's plenum.

Pushing cover downwards, remove  screws around the regulator cover, then release slowly.

Remove the cover from the diaphragm. Note that the diaphragm is broken

New diaphragm (left) and the old one (right).

Place new diaphragm in the cover, and install, tightening screws in a cross sequence pattern.