No. No. Have not added any aftermarket mods. Am not driving like a maniac all of a sudden. 10k on a 2009 MC standard. Have been consistently getting upper 30mpg. That equates to about 450miles/tank. Last tank was 398 when I hit the red petals.

Routinely, I don't lose the first petal until about 110-115 miles after filling up. This tank it was 89.

No noticeable difference in performance in any regime. It's a mystery.

Ideas??

 

Could be the result of the winter conditioned / E-10 based (ethanol) fuels we are putting into our cars this time of year....

Dope heads who came up with this genuis idea of putting Ethanol into our gas tanks never took into consideration the fact that it would lower our MPG and drive up the costs of corn products. It has been said that our car's software in the UCU's were not originally programmed for this fuel mix and thus they start stumble, sputter and have un even idle at times....

Some Motorcycles run like crap, as does chains saws, gas powered landscaping tools and other small gas powered engines.......

You can thank the Global Warming Scam Artists for that too.....

 

I had a similar dropoff a while back that I attribute to a change in tires. However, while not as dramatic, previously when I noticed the mpg starting to drop off, I'd run some fuel injector cleaner through with a tank. At 10k, you might be due. If you try that, I have found that I don't usually see an improvement until one or two tanks after the tank with the cleaner. And you should be seeing a slight dropoff now due to the winter gas.

 

+1

 

Fuel formula change is a likely answer, but another one is that the auto shutoff just tripped off a little early when you filled up.

 

Auto shutoff maybe, except this is the second tank. Possible. The mpg indicator did read 41.4 at the last fill, which is more consistent with the higher total miles at 2 petals.

Change to E10. OK, but it doesn't run badly at all. And don't they use E10 during summer? Ran well all summer at the higher mpg.

Dirty injectors? I use Chevron and Shell just about exclusively. I thought Techron was supposed to do a good job. Still, I'll pick up some cleaner and drop it in tomorrow.

Will keep tracking and let you know if I figure anything out definitively.

If any other ideas pop up, please send.

 

I have found my car is particularly sensitive to city v. highway driving. I commute daily on the freeway and can get high 30's for MPG, but if I do more driving/errand running around town, I can lose as much as 5 or 6 MPG per tankful (as far as the on-board computer is concerned).

 

Winter blend (10% ethanol) always lowers my MPG.

 

^^So does my right foot