05 MPG down to 35...what's wrong?

How often do you check the tires? What are they now?
Do you ever check the oil level yourself? What is it now?

 

Engine air filter ?
Poor gas ? Increased % ethanol ?

 

If the parking brake is not dragging then I wonder if the OP drives in the EV mode too excessively to the point that the health of the HV battery is damaged.

There was a national lab study showing no MPG impact by very dirty air filter on modern cars with computer controlled ICEs.

 

By "EV mode" I meant

. If one drives with yellow arrow only from battery to wheels for a long period of time then the HV battery may be stressed.

By the way how is Tapatalk working for you?

 

I am in south florida too and I am getting about 35mpg too....
Two weekends ago I took a drive up to orlando and got 47mpg- last weekend I was stuck in very slow moving traffic on 95 and got close to 60mpg.

I dont think there is anything wrong with my prius or yours for that matter- south florida sucks nice person when it comes to the roads. At least in the ft lauderdale area, you get slammed with lights everywhere and can never really cruise enough to get proper gas mileage. Not to mention that it has been so hot (close to 100).

The slow moving stop and go like in bumper to bumper traffic is great because the battery does all the work, but ive noticed that the lights down here are not timed in any sense of the word so often you have to accelerate from a stop, make it roughly 200ft and are stopping again. Unless you do one of those reaaalllly sloooow egg shell on the gas move, this will kill the gas mileage.

 

Hmmm.... at 35 - 45 MPH one would expect 60+ MPG unless it's all short trips or stop and go traffic.

There are cases of A/C failures but I haven't heard of cases of inefficient A/C causing MPG drop but then again anything is possible I suppose.

Have you checked the parking brake drag? That would be an easy one to fix.

I can say typing on an iPhone is even worse.

 

According to this document
http://avt.inl.gov/pdf/hev/prius2004hevamerica.pdf
fuel economy drops from 53 MPG (no A/C) to 41 MPG (max A/C).

 

Thank you...I've checked on the 2010 Prius and
http://avt.inel.gov/pdf/hev/fact2010toyotaprius.pdf
15 mpg 65 to 50...
Still not BAD !

 

Thanks for the updates. So now we turn to the weather: MPGs on mine have also dropped during the last three weeks of 100'F+ temperatures. The heat inhibits the battery system, so stop-and-go fuel economy suffers even more than usual, and of course it makes the A/C work harder. At night when it's merely 90'F or so outside and the highways are clear the MPGs go right back up.

Does any of that fit your circumstances? If so then the cure is called "October" :_>

 

What are the make, model and size of tires you have now?

Do you remember what you had before? Where they the stock Goodyear Integrities that came on non-tourings?

 

Has parking brake drag been ruled out yet?

How about a weak HV battery?

 

If the oil were 2/3rd's up to the full mark it would yield optimum mileage.
I'm thinking something funny is going on with your cooling system, check to see if the trans axle recirculating pump is working properly. Human mechanical mistakes are not out of the realm of imagination.
Clean your cabin air filter.
Cycle your emergency brake on and off a few times.
Change your trans axle fluid.
Did you put an optima or original equipment battery in?
(An OEM battery isn't going to last, it's money down the drain.)
Do a fresh reset of your mileage total, if it's getting better mileage now a low average would take a long time to overcome.
Change your engine air filter(clean it if it's a K&N filter).
One misfiring spark plug would yield this type of mileage but should show up as an error when reading the OBD11, but stranger things have happened.
jmho,ymmv

 

Unfortunate and typical dealer reaction. This problem has been a recurring one since 2001. Congradulations on the dead battery right at the dealership, I did the same thing in 2005.

 

Have you checked your engine/cabin air filters? If your running the A/C, perhaps a clogged cabin filter is reducing the A/C efficiency.

And finally :has your commute changed? Shorter trips?