Hello again,
The fuel pressure regulator is controlled by engine vacuum. If there was not a vacuum line attached to the regulator that was in your vehicle, that was probably the problem. I would definitely try to locate the vacuum line or you will have a major vacuum leak which will cause any sort of idle and driveability problems. Just follow all the vacuum lines around the engine, they should all originate from the throttle body and you will come across it. If not, you can pick up vacuum line and T fittings at any auto part store. Just cut the vacuum line anywhere, insert a T fitting, and then run vacuum line to the fuel pressure regulator. In the diagrams down below I have included the instructions for the removal and installation of the fuel pressure regulator from the vehicle manufacturer. Please go through this guide and get back to us with what you find out.
Thanks,
Alex
2CarPros
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Wednesday, October 16th, 2019 AT 12:35 PM