Well, don't panic just yet...

Several of us have noticed a subtle but definite change right around the mileage you have on your rig now. It's kind of like the computers are all finally synced up and agree on how much battery you can use. My mileage has improved measurably over the last few tankfuls. I'm just about to hit 5000 and I think this tank will be in the 28-29 mpg range...