XJB, I'm questionable as to how well that guage works. It read 34.4 or 34.5 on my first tank... and then actual mileage was a little over 36. On my second partial tank it read 35.5 and we got 38. (It's reading 35.5 now... but we are only 100 miles into this tank.)

We filled it with regular this tank. We are going to do a tank or regular, then one of medium... then one of high octaine... to see if we can see any difference in performance.