I replaced a fuel pressure regulator on an '85 22re 4runner without removing anything else. I don't remembering it being easy, but it can be done.
Well... I stared at this for about 30 minutes. I looked at the pressure regulator from every angle, and I cannot see how I can get a wrench on the hex part of the regulator to loosen it and re-tighten it. Obviously its doable... you did it. It needs to seat with the fuel rail very carefully and with the right amount of torque so there is no fuel leaks. An open end wrench looks like the only tool that will work?
If there is a trick to getting to it and R&R'd without removing the chamber and throttle body, I'd like to know what it is.