Well I really don't know what else it could be at this point... if everything after the regulator is clean and clear, and the fuel pressure is wonky at a constant RPM even with the vacuum line off, I feel like it would have the be the regulator that's causing the problem..

And since the diaphragm seems fine, I have to think there's a problem with the spring.


Thinking about it from a different angle though: what if it's just the gauge that's fucked? Would the fact that the engine's burning off some oil and assembly lube be enough to keep the wideband buried on rich?