MPG increase

So my EGR valves kaput, and while waiting for the replacement I capped the cavity with a piece of tinplate and permatex copper gasket. Am I seeing things or did my gas mileage just go from 27 MPG to 33/36! I drove 156 miles and used 4.2 gallons. My next checkup was 181 miles on 5 gallons. (thats Can. gals = 4.54 litres) My cam sensor is also kaput (on order) which brought the original recommended MPG down as expected from 35 highway.

The only other thing I did was shoot a 1/3 bottle of Seafoam carbon cleaner from NAPA into the intake,1/3 into engine and 1/3 into gas tank as prescribed before clocking these miles.

So wheres the saving to the envoironment if I use 30% more gas with the EGR connected?

Whats going on? I don't care I'm saving a bundle.