Decreasing gas mileage

[hammersc]

I have an '05 t4r (limited v6, S. Carolina). I used to get 400 miles on a tank no problem. Over the last 6 months (45k mi now), mileage has gone noticeably down. Averaging like 350 instead now (always a pretty consistent mix of hwy and city miles on every tank). My onboard computer says I'm getting 20.4 mpg over the life of the vehicle, but lately it's way down from that. My driving style hasn't changed, it's still a pretty even hwy/city mix on each tank, same regular gas, etc.

Anyone else seeing a decline in gas mileage? Do cars get more or less gas efficient over the life of the engine?? I just figured gas mileage would stay the same, ceteris peribus.

 

[armyguy872007]

I have an 05 V8 2 wheel drive and averaged 19.3 on my trip to Wisconsin this weekend, My "To Mileage" shows 336 when I fill up which I beleive equated to 400 with the 2.5 gal left in resivour. Hope this comparison helped, I had the cruise set at 77 and my ave speed was 74 of course this is going through Iowa for 300 + miles of the 565 miles traveled 1 way.

 

[<<<<]

2004 V-6 4WD SE here, average 14 mpg on 89 octane gas. All city driving plus winter gas. I don't sweat it any more because it is 5000 lbs vehichle.

 

[simple]

2004 V-6 4WD SE here, average 14 mpg on 89 octane gas. All city driving plus winter gas. I don't sweat it any more because it is 5000 lbs vehichle.

While I certainly hope I don't ever hit 14mpg... yeah, mine has gone down recently as well. I figure its the winter gas as well...and there's no point in getting super hyped up about it.

When I want to get close to 400miles per tank, I try to get everywhere by not going over 2000rpms. As far as I know, that when my vehicle runs the most efficient.

 

[boston_kevin]

Two things hinder gas economy in the winter - winter fuel and colder temps. Colder temps means denser air which is more difficult to push. I see this every year and then in April my mileage gets back to normal.

 

[cwest94]

Ya, mine has been going down as well. I was getting around 18 to 19MPG with each fill up, now I'm getting 14.5 to 15.5MPG with each fill up.

I hope it's from the winter gas like others had said, so I'm waiting for spring time to see if the MPG changes for the better.

 

[GYoter]

Mine has gone down over the life of the car as well. Im lucky if I get 300 to a tank. Used to get 320-330.

In the winter I try to not pay attention since I tow snowmobiles in the mountains. I am lucky to get 200 from a tank towing.