I am the proud owner of a 2007 Prius. Love the car handling etc. BUT... Something is progressively going bad. When I first got the car it was averaging about 44-46 MPG for the first 10-15K miles. Sense then the mileage has been steadly droping.So naturally I went to the dealer. He said I needed to replace the engine air filter and do a four (4) wheel alignment. We followed his recommendation and let him do the work. Noticed a slight improvement 2-3 MPG. I do keep the oil properly changed and tires inflated (if not somewhat over). But as my luck after about a month of driving MPG has been in a real tail spin. As of right now the car is averaging 33-35 mpg and nothing I seem to do helps. (30K miles on the car now). I drive 2.5 miles to work and sometimes take trips to Home Depot or Lowes etc. about 2-3 miles. But, that's nothing new. I've been doing that ever sinse I've had the car. If someone has some ideas I sure would appreciate it. Thanks.
There are several threads on PC that discuss dropping MPG but one item that seems to pop up with cars that are several years old is the 12v battery wearing out and requiring frequent recharging that results in your engine running more than it used to thus the burning of more gas. Also along that same line is the outside posibility that the cooling vent on the rear passenger side is getting blocked with dusk and animal hair. Also are you using more AC now than in the past due to warmer temps ?
Two to three mile trips are going to produce lousy mileage. A significant percentage of your fuel is being consumed to warm up the engine. The figures you report are about what I would expect to see for a Gen II driven such short distances. On the other hand, you aren't burning much fuel with such short drives. Tom
Thanks Snead. I'll have the vent and the 12 volt battry checked. I'm the only one that drives the Prius. Her's is a 2010 BMW X-5.
Thanks Tom I kinda figured that a slow 2.5 mile trip was a major factor. Although, down here the average 7am temperature is about 90 degrees. :welcome:
Might want to also double-check that the engine isn't overfilled with oil. I just drained out an extra quart (or maybe a quart and a half) from my wife's 2008 prius last night. Darned dealerships are so dumb about that and it happens all the time! Other possibilities I could think of would be sticking brakes or bearings, might jack up each wheel and see if it spins freely. Also maybe hook up a scantool and check for any pending codes. A bad oxygen sensor or the like could also cause that.
Dealers often don't test the Prius 12V battery correctly; their testers may accept a voltage much lower than that needed to keep the Prius electronics happy. But you can easily test it yourself with no tools using the built-in procedure: http://priuschat.com/forums/newbie-...g-mpgs-dropping-test-battery.html#post1154193 Grossly overfilled oil and low tires are always suspects. Are you using the A/C a lot more than before? OR, is the weather a lot hotter now and you're *not* using the A/C at all?
