Fuel pressure regulator?

You can continue to throw parts at it until you are broke and probably still won't have it fixed. You need to do some testing starting with pulling the codes and reading the fuel pressure.

http://oldfuelinjection.com/?p=13

I seriously doubt you have raw fuel coming out of the tailpipe. It would never make it all the way through. Your probably just see condensation dripping.

Are you sure that couldn't be leaking from the fuel tank? Never in my life have I seen fuel get all the way through and a catalytic converter and a muffler. The Converter gets so hot that it would ignite long before getting through it anyway.
You certainly could be having some kind of flooding problem and that would take an injector balance test to determine if one was leaking. Usually when that happens, the gas runs down the cylinder walls and into the crank case and dilutes the oil and not the exhaust system.

You can do some testing with a fuel pressure gauge to determine if you have a pressure loss anywhere but I don't have much else for you. It just doesn't add up to anything I recognize.

Let's see if anyone else here has any ideas. In 40 years of doing this, I have never seen raw fuel get all the way through an exhaust system without burning off first in the converter.

It shouldn't be that difficult do determine where that volume of fuel is coming from if it is. I suggested doing pressure leak down tests to find out but apparently your not interested in doing that.