29mpg cross country.

Did the dealer check and clean MAS, air horn, oil level ( correct level ) Now analyze what has NOT been done for awhile. I see this is your first post, Ever change the 12V battery? Next assignment: Read all post on PC concerning mpg. Next: Read all post on regular maintenace, this should keep you busy til hit the coast.

 

Tule bag plus headwind plus speeding could cause dramatic loss in mpg.

 

When you did this trip before and got 40 mpg, was that with the Tule (Thule?) bag on the car?

 

we did a trip from nyc to family in indiana with a roofbag. our mpg was low 30s due to wind. once bag cam off car back to to 45-50. the bags seriously effect mileage but we only use them once in a while so i wouldn't be overly concerned.

 

+1, esp on checking/replacing if indicated 12V battery. (~$200 at dealer.)

Heavens to Murgatroyd!



This situation is similar to heading for the North Pole and not thinking
you will need a sleeping bag until you get to Fairbanks.

I presume you aren't of a mind to stop for any length of time on the
road, so here are some "on the fly" items that might help hold/increase
your FE/MPGs:
* Pump the tires up to 42F/40R (Check the spare. IIRC, 60psi.)
* Check oil level -- just below the 'Full" bump is best
* Keep windows closed
* Check intake air filter -- if dirty, maybe a service area mechanic will
blow it out for free (Remove filter from intake air box for this. Ensure
it is re-installed right-side up and snug.)
* Drive as slow as your family will permit. The Gen II sees a serious FE
decrease above 65 MPH.
* Use Cruise Control except on steeply hilly/mountainous sections --
except for the very best high-speed hypermilers, CC does a great job
on FE/MPGs.
* DO NOT allow the HV battery air inlet vent on the passengers side
of the rear seat to get blocked.

Remember P^6...
Prior Planning Prevents Piss-Poor Performance

Good luck, and drive safely. :rockon:

 

That's not very specific. There's a reason why I put up http://priuschat.com/forums/gen-ii-...-answer-these-questions-esp-if-youre-new.html.

Unfortunately, your load on top is adding significant drag. It's be interesting to know your mileage (and info about your trips, tires, oil etc.) once your load on top and any roof rack is removed.

There are a bunch of things you can check and reply back on in the meantime such as 12 V battery level, make, model and size of tires, oil level and viscosity last used.

 

Post 8 covered everything well, search MAS (Mass air sensor). 12 V battery. All covered previously in quantity on Prius Chat.

 

are you going north or south?

 

or east or west?!

Elevation changes + wind + drag + speed = poor prius fuel economy

Poor prius fool economy >> average fuel economy in any other vehicle

Our normally average 24-28mpg RX350 gets 17mpg to 18mpg driving cross country with no bag on the roof.