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Oddly, at 75 MPH I can make the counter read right around 33 MPG, at 55 MPH the best I can get is right at 30 MPG.


That doesn't have to sound that odd, you are doing more miles per hour with the same engine effort. That vette has a big displacement and torques like a big rig. If it's no difference in effort on the engine doing 75mph over 55mph the display will show more mpg because you do more miles per hour using virtualy the same ammount of fuel. My JGC does that sometimes when the circumstances are right.

1987 SWB Pajero 2.5 TDI on 31" rubber waiting for a hip replacement and bigger shoes