Running rich, P1176 code
 

As the title states, I noticed recently my discovery as been running a bit rich. Gas mileage has been down by 2-3 mpg according to the ultra gauge. Also, it has occasionally thrown the code P1176, which I understand to be the ecu is putting the max amount of fuel that it can into the engine. Recently, due to other reasons, I have been hunting down vaccum leaks, but have had no luck in finding any. Has anybody else had this issue and would be willing to help figue this out?
Thanks

I had this problem. Check the vac line from the fuel pressure regulator to the manifold. It took care of my 1176 as well as a purge valve code and o2 heater circuit code. Also try cleaning the MAF

I just replaced that vac line for the fuel pressure regulator. It didn't help. For anybody who has an ultra gauge, what are the normal mass air flow g/s readings?