is 4 or 5 psi less fuel pressure enough to cause a po171 code on 2002 Buick LeSabre

checked fuel pressure,only at 44 psi so I changed fuel pressure regulator. now it's at 50 psi. my car calls for 53-59 psi. only regulator I could find is rated for 50 psi. is this difference enough to cause a po171 code

Asked by for the 2002 Buick LeSabre
yes it doesnt take much of a fuel pressure drop to cause problems if it still not running right then clamp off the return line and see if the pressure goes up