Went from 53mpg to 44 one one tank.

[Gasitman]

I always use shell, or Costco gas and I have gotten between 50-53mpg. I was somewhere I had to fill and I went to a Citgo and now I am 44mpg per tank. How can the gas be that bad to drop so much? With the exception of Sunday, I am traveling the same route everyday as I had been.

Only thing I can think is the defroster has been running a lot with the rain, but would I loose that much mpg?

[Bobsprius]

Originally Posted by Gasitman

I always use shell, or Costco gas and I have gotten between 50-53mpg. I was somewhere I had to fill and I went to a Citgo and now I am 44mpg per tank. How can the gas be that bad to drop so much? With the exception of Sunday, I am traveling the same route everyday as I had been.

Only thing I can think is the defroster has been running a lot with the rain, but would I loose that much mpg?

You really should only see a couple MPG difference IMO. I know that the gas formulations are changing sometimes at this time of year and there is more Ethanol (upt o 10%) but that should not have made that much difference.

I have been reading some of your posts about mileage, and am not sure why you have such a spread in MPG's? Did you reset your TRIP B odometer at fillup and are watching from a reset??

Have you been taking any more short trips? Colder Temps?

[F8L]

Did your other tanks involve the same amount of rainy conditions? Rain and wind can kill your milage like no other!

[Tideland Prius]

cooler weather, winter fuel (maybe your last tank was on summer fuel), defroster (which means A/C is running but then again the new A/C is a lot more efficient)

[Gasitman]

I reset it before I move from the pump. And yes, there is much more rain than before. I cannot believe the defroster, with the AC running would tank my mpg. I don't know, I just cannot see what I am doing wrong, I run the same 77 miles everyday, and nothing more. That is with the exception of Sunday, but I cannot see how that would make a difference, considering it was my same route, just with 25 miles less, I ended up not going to my second destination as I do the rest of the week.

[spiderman]

I have lost about 4 mpg since the end of summer. Hard to see why you lost 9. You might start your tank over with costco gas and see what happens.

[Tideland Prius]

Originally Posted by Gasitman

I reset it before I move from the pump. And yes, there is much more rain than before. I cannot believe the defroster, with the AC running would tank my mpg. I don't know, I just cannot see what I am doing wrong, I run the same 77 miles everyday, and nothing more. That is with the exception of Sunday, but I cannot see how that would make a difference, considering it was my same route, just with 25 miles less, I ended up not going to my second destination as I do the rest of the week.

I'd say outside temp more than anything. I went from 4.0 to 4.4 (59 to 54mpg) thanks to temps cause the engine has to run longer to warm up. No defroster use yet and I have the grille blocked.

[ALS]

I have to agree my fuel mileage has dumped in the last two weeks. Temperatures are down twenty to twenty five degrees in the morning and it was been very rainy. Add to that I have a tank of E10 in the car and there is almost no way to win.

Last tank with temperatures higher by fifteen of more degrees and a tank of straight gas I averaged 53 mpg (HSI display). I'm lucky if I'm averaging 48.5 mpgs right now. It is so frustrating not to be able to raise my fuel mileage on my daily trips around town.

[F8L]

Originally Posted by Gasitman

I reset it before I move from the pump. And yes, there is much more rain than before. I cannot believe the defroster, with the AC running would tank my mpg. I don't know, I just cannot see what I am doing wrong, I run the same 77 miles everyday, and nothing more. That is with the exception of Sunday, but I cannot see how that would make a difference, considering it was my same route, just with 25 miles less, I ended up not going to my second destination as I do the rest of the week.

That alone could explain your problem. Rain can tank your milage because you are using energy to pump water from the tread in your tires. This is wasted energy and you pay for it with petrol.

If you had headwinds aw well you would suffer even more loses. Bad weather can be almost as bad as going up hills. lol

[Gasitman]

but 9mpg??????