Chrysler Repair: Poor MPG after EGR Valve change, gas mileage, grand caravan

Question
About two months ago I changed the EGR Valve on my 2006 Grand Caravan after codes P0404 and P0406 came up on a scan.  Ever since I have notices a slight reduction (2-4 mpg) in my gas mileage.  Is there anything in particular that may be causing this?  I used the video http://www.youtube.com/watch?v=DXL3QFaqPZ0 as a guide but did not remove the alternator, I was able to slip a socket around it to get it to loosen.

Answer
Hi Steve,
If the engine otherwise seems to be idling and running well I would not think the mileage issue has anything to do with the egr. You could check for any new fault codes. And of course local driving conditions and weather can affect mileage, and even changes if the formulation of gasoline depending upon the time of year can affect mileage. Tire pressure might be involved, too. So check out these possibilities.
Roland