what model year do you have? if a second gen, are you checking the dash mounted mpg or the one on the center dash? they can differ betwixt the two.

well, did your driving habits change? what about the weather? are you driving less? are you using the same petrol at the same station or do you mix it up? did you modify your car or do any maintenance?

why did you start using top tier? how may tank fulls have you had of it? it may take most of the tank to notice any improvements, especially if you have 87 octane in there.

despite what you may think, higher octane petrol does have its merits -- it helps to prevent premature detonation. this allows the engine to produce more power. lower octane can cause knocking -- the knock sensors tell the computer to retard timing. this reduced timing can lead to lower mpg and less efficiency.

all this to say your driving habits will help you improve petrol mileage. your car is what 6k ish pounds or close to it? its heavy and likes to drink so unless you drive 30 miles per hour and slloowwwlllyyy ease off the line at the red light and avoid hills, keep the hvac off, you wont get honda accord type mpg..

 

I have a 2023 SV. Nissan recommends premium fuel for "optimal performance" and I'm thinking that one of the reasons why some people are getting bad mpg, is because they are using regular and the computer is adjusting the engine timing enough to negatively effect fuel economy?. Also, with the SV the tire size is slightly narrower with the 265/70-18 vs 275/60-20 or 22's. Maybe less rolling resistance?. My average results are over a 7,000 mile run, I live at 7,000 ft in Colorado, and the computer is always within 1/2-1 mpg of the calculator sometimes favoring the computer! I'm not complaining for sure, just wondering why I hear so much complaining about fuel mileage.

 

The highway fuel economy rating for my 2021 SL is 19 MPG, so you are not far off if your travel is all highway. Combined is 16 and city is 14.

 

20mpg sounds like a dream right about now. Dash says 15-16mpg but I'm running bigger tires and the math at the pump came out to about 14mpg. And I'm using regular 87 octane

 

Bigger and heavier tires will kill gas mileage for sure.

 

So I have a Patrol in the Middle East and it comes with an eco button, All that does is shift gear as early as it can and it hardens the accelerator pedal a lil bit. 20.6 Mpg converts to 8.76KMPL which is what we use there. I can tell you that I have gotten much better gas mileage with eco mode turned on and driving at 45 miles an hour. The dash has shown me 16.7Kmpl when I drive moderately and when I convert 16.7 Kmpl it comes to about 37.6 MPG. I know it sounds almost impossible but it is achievable.

 

05 w/200+K....used to get 17ish hwy in the 70-110mph range. Lately its getting more in the 15-16mpg range. Still original plugs and all.

....but I drive it like the hounds to the hunter.

 

I get 12 and thats it

 

I did a very unscientific test on my new 2024 Armada Plat. Had a long trip planned. I calculated it would be at least two full tanks. Trip out I used regular. Trip back I used premium. With regular my MPG was 13.4, with premium it was 15.7. I paid $18.20 more to fill up with premium but extended my range by 60 miles. Cost per mile for regular was 21 cents. Cost per mile for premium was 18 cents. This summer I have a 2,000 mile round trip to Colorado from home base in Texas. I should save about $60 using the more expensive gas. Never would have believed it. I will make a full report upon my return.

	REG	PREM	DIFFERENCE
JB EXPER MPG	13.4	15.7	2.30
COST PER TANK	$ 73.84	$ 92.04	$ 18.20
MILES PER TANK	348.4​	408.2​

 

Interesting. I would probably go with driving habits.

 

I get 19mpg highway with my 2013 qx56 with 87 octane regular. Premium only makes a difference in acceleration, steep hills or pulling a trailer.

Average mix is 15mpg. The short trips are 3 miles each way shopping so that hurts a lot. This year's computer is pretty spot on.

IMO driving habits influence mpg way more than fuel.

 

2019 Armada SL. Regular octane getting 18.1 mpg. Might run some premium when I pull our new travel trailer.

 

Reply to Lamos1. I would be OK if you were correct re driving habits. I am a very defensive driver and not a speeder (one and only speeding ticket was in 1987, in a school zone I did not see). Brother says I drive like an old woman. I handle tort claims for a $4.7B university system, so I have seen the carnage of bad driving habits. Took same route, and traffic was about the same each way. Load was the same. My best guess is it was not driving habits. Wish it was because I can control that variable Thanks for all the input members!! jb85