If you run less AFR, while being less efficient.....it uses less fuel.
Reptile,

I don't understand the above quote from you. If you are saying with the EGR, it is less efficient, it should use more fuel. But you say less efficient means it uses less fuel? I am confused.

In my experience, I left mine on my car since I never had a reason to take it off. But I developed a crack in one of the EGR tubes, and it created a massive vacuum leak. So instead of replacing the tube, I just removed the EGR valve. I used my PT and returned my VE, MAF and timing, and I did not notice any drop in fuel efficiency. Again, this is my experience.