Yes-----

Winter formulated gas. I don't know the specific details, but at some time in the fall each year, the formulation is changed and everyone's mpg goes down. You'll see in spring, especially after yours is broke in the fuel mileage will go up, and I have no doubt with the MDS you'll see mpg's in the 20's if you keep you foot out of it now and then[sm=gears.gif].

 

I believe<?>theyincrease the ethenol blend in the winter. Ethenol does not produce as hot of a spark as pure gas, this results in a decrease in power and mileage.

 

Yes the winter fuel blend really kills mileage. I get about 3mpg worse in the winter than I do in the summer. 15mpg summer and 11-12mpg winter.

 

hey guys i ave. 18/19 all the time but i have a 4.7. i believe the winter gas thing is true. also running 3.92 on the highway will net lower gas mileage compared to 3.55 but not much. 13 mpg is kinda low. had a 97 5.2 that got great mileage. still turning 17/18 around town and 20/21 on highway with 165000 on it.

 

Several times I thought I had achieved 18 mpg and once 21 mpg. This was based upon using the odometer and the amount of gas actually pumped into the tank. After congratulating myself, the next run would invariably be really low--13 to 14 mpg. I noticed a lot of inconsistency--same drive, same conditions, only 15 mpg.

Since I have meticulously recorded every tank of gas I have ever purchased on my 05 1500 Hemi, I could see the patterns. Then, by chance, I had a 20 mpg run. I went back to the same station that I had just filled up at. Added another 3.5 gals. Oops. 15 mpg. After that I noticed that some pumps cut-off when the tank can take several more gallons. Sometimes, the pump cuts off when the gas is all the way to the filler neck. It wouldn't surprise me that some folks that get a high MPG on one run, might be experiencing some of this kind of "help" from the gas pumps.

I did a 5,500 mi trip this summer and meticulously filled the tank till I could see gas "staying" in the filler neck. Sometimes this would take 10 minutes or more of filling--it drove my wife crazy. At the end of the trip, overall MPG on virtually all highway, summer 90-100F, with A/C, flat 65-70mph, gas mileage was 15.1 mpg.

Every now and then I still get a 18 mpg run, but nowadays, I just shrug it off and expect the next run to be 13 mpg. :-)))

 

my hand calculated best on 87 octane was 20.4 mpg. Overhead said something like 22.2 mpg. This was a fairly short trip though, so as somebody stated earlier the tank may have filled to a different point when it stopped pumping. I would say conservatively though that it was easily 19 mpg.

 

Remember your overhead is giving an average.
Hit the reset button to get a new average when you are cruising for a mileage reading.

 

Winter fuel has MTBE added which is an oxygenator. That's what makes the mileage diminish. Sometimes for carb'd engines you even need to adjust the idle mixture to run the MTBE fuel.

 

I thought the Gov. banned MTBE and switched to ethanol? That was the case here in CA that stuff was eating through the fuel tanks underground and seeping into the ground water supply. Most gas stations had to replace their storage tanks.

 

I get 17 to 19 MPG pretty much all the time, mostly highway , driving speed limit, and yes the MDS does not work over 65 MPH