Seven months with my '10 Prius

Did you read the MPG numbers on the car's display, or calculated at the pump? I got my car 6 weeks ago. Now the average (1900 miles strictly for weekday commute in DC's terrible traffic) is 49.3 on the display. But my calculation by gas station receipts is about 45. I am using 87 gas.

 

You might want to check the lock assembly for the rattle. I believe it's the plastic arms of the lock that vibrate and cause the rattle.
FYI

 

On average over 7500 miles my computer reads about 2 mpg high.

 

Musigny,

I've just been running 87 in mine without an issue at all. As far as fuel economy goes, I got mine at the beginning of October. I was getting around 48-49 on a completely green engine. Now that the temperature has fallen off, I'm getting around 42 or so (mostly short-tripping). I can't wait until summer when I can see what it does once it's completely broken-in!

 

I don't know if this is because of changes in weather or fuel, but I noticed a sharp decline in fuel economy in November. It's been as low as 42, and it takes some effort to hold at 45-46.

Cooler weather will definitely cause a decline in fuel mileage, and to the magnitude that you've seen (or more). There are a number of threads you can find in the fuel mileage section (of both the 2nd and 3rd generation forums) that will document this. There is one person (in a gen 2 thread, I read it yesterday) that was getting 29 mpg in Alaska right now (after getting mid to upper 40's in the summer).

 

As mentioned in several posts, gas mileage in the Winter will drop for two (primary) reasons:

(1) The engine runs more often to maintain proper engine temperature and to heat the cabin. It also will run longer when you first start the car after the engine has cooled off. The fuel efficiency of EVERY combustion engine is compromised/reduced at colder temperatures.

(2) Change over to 10% ethanol gas (a.k.a., "Winter Blend")


Rest assured that while the Prius MPG's will drop in colder months, so too does the MPG for every car on the road.

Knock on wood, but I've never gotten below 50 MPG (calculated or measured) at anytime during the last 2,900 miles.

As far as the rattle is concerned...in prior cars where the glove compartment rattled, I've packed in paper towel, rags, etc to put pressure on the glove box door (ie, will minimize any rattles coming from the glove box latch).

 

"Too many rattles. My car (package III with navigation) rattles like crazy, especially on the freeway. It sounds like it's coming from the glove box, but it's in the dashboard and not something I've put inside the glove box."

I've had my car just a month less than you have (by my calculation,you've actually had yours 6 months, not 7), and haven't had any rattles whatsoever, but I feel that if I did I'd expect them to be located and fixed by the dealer. I hope you can get yours corrected!

I've experienced the Nav not providing turn-by-turn assistance in certain areas and occasionally not recognizing the DVD at first. I hope that can be addressed when I bring it in for the 5,000 mile servicing.

I also hope that at the servicing the headlight aim can be raised so I'm not outdriving the low beams as I am now.

Finally, I'd like to see the delay corrected that occurs when answering the phone on bluetooth, but I realize that's not unique to my car.

Otherwise, I find it to be just delightful and to have great mpg. I like all the strange noises, especially those that come from the back in the middle of the night in the garage, and the one that occurs when I open the driver's door in the morning ("winding itself up," we call it).

 

How many miles are on the car?

 

I'm obsessive about chasing rattles and fortunately our BP-V/nav has only had one. I had initially thought it was a dash rattle but it turned out to be in the rear view mirror and was easily addressed with a small piece of foam.