I keep very detailed mileage records on all my cars. I do a mixture of city and highway driving, but mostly city (perhaps 60-40 balance).

So after 12385 miles my 2017 LT-1 on average I'm getting almost 16 mpg. Not bad and I'm satisfied with that. But here is the strange part. If I break it down by city/highway, city, and just highway, my highway mileage does not come close to the EPA rating which I compare to.

Here is snapshot of my spreadsheet. The best I ever achieved on the highway is close to 90%. Whereas on city and combo I have exceeded the EPA rating on several occasions. My instinct's tell me that the city driving should be low and the highway should be over the EPA rating. I usually cruise at about 60 to 65mph. True if I reset the mileage minder to zero on each highway drive I'll get close to 20mpg but never the 22 as rated.


Any thoughts? Just curious.


On all my other cars (be it Fords or GMC brands) I can almost always beat the highway rated MPGs.

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Can you verify what your RPMs are at 60.
Possible youre not going into 6th.

RPM's seem normal. Below 60 I'm usually under 2000. At 65 to 70 I range at about 2500 to 2700 rpm. I think that's typical. Engine temp is a steady 270. Everything runs fine.

If I recall correctly- @ 70 MPH, im at about 1800 RPM.
Normal engine temp on the gauge should be near 210.
when using a scan tool- you may actually see about 195-200.

found a post I made....for my 2010.



Jul 18, 2013 just got off the highway.
Did a quick look

at 60- about 1550 RPM.
at 65- about 1600 RPM
at 70- about 1750 RPM

data I gathered from my OBD port.

here are my shift points when driving down the street. In no hurry.


Ill shift into 5th gear at 41 mph.

My mistake, 210 is the temp not 270. And I'm off on the RPM's also. Once I'm up to speed it hovers just below 2000.

Oh good... that’s about normal. Otherwise you are grossly overheated and driving in 4th gear....maybe 3rd.

In my "extremely humble opinion" 16mpg really stinks. Mileage on my 15 LS with 56k is between 16.9 & 18.7. Understand that it is a big, heavy vehicle........ but...... gotta a 97 Plymouth G.V. with 285k and a 41te tranny that still gets 19 to 21mpg.

Live 1 1/2 miles from interstate and 10 miles,minimum, from town. So most of the driving is around 75mph, average.