Significant Drop In Gas Mileage

popptj · 01-19-2008, 01:37 PM

I have an 07 Prius PKG 5 with 30K. The car has performed great up until now. Over the past week or two gas mileage has dropped into the 30's at times--38-40. I have not changed anything. Oil levels are fine, tire pressures are fine, etc. I notice that the battery stays green quite a bit...I read somewhere seeing a green battery is rare. I live in south Texas and it is cooler..but it's not crazy cold. Temperature has been in the 50's.

Something isn't right. The electric/gas motor isn't coordinating as it should. To the dealership?? I can cruise at 60 and the meter is hanging in the 40's. Every now and then it will register higher mileage...say going down a hill or decline, but on level roads, nothing like before. Help appreciated.

**Tideland Prius** · 01-19-2008, 01:39 PM

how long have you had the car? i.e. have you driven it through the cooler "winter" months?

cause at 50°F, the engine will run more often.

DaveinOlyWA · 01-19-2008, 01:49 PM

hard to answer without location posted... many areas of the country recently went thru much cold than normal weather. are you in one of those areas?

popptj · 01-19-2008, 02:02 PM

Temperature is 60 degrees currently and still having the same problem. I am convinced something is wrong mechanically. I have heard about "flashing" the system at the dealer. Any thoughts on that or other potential fixes?

I have driven it in similar weather before here with good results a month ago or so.

DaveinOlyWA · 01-19-2008, 02:08 PM

60º.... ya, even if you drove like a maniac, you probably couldnt do worse than 40 mpg as long as you kept it under 70... i would have it checked along with tire pressures.

my mileage took a dive once, more than 5 mpg... found out that had a tire down to 21 psi from 40... will say one good thing about LRR tires, they keep their shape well even with little air pressure

uncool · 01-20-2008, 08:08 PM

Im in the bitter cold of Chicago where my high 40s mpg are currently low 30s.

AOV · 01-24-2008, 07:36 AM

Winter and the heater is ruining my mpg's. Use to get mid to high 50's on a regular basis during the milder weather, now that it is 20's and 30'sF here, and with numerous short trips (less than 15 min. round trip) my mpg's are low 40's. Just came back from a 500 mile round-trip (highway mostly) and only got 45, used to get a lot more. I keep the cabin air at about 73 degrees.

gazz · 01-24-2008, 08:28 AM

Its colder in the UK and I have dropped from 65s to 55s. Does not matter what I do it just will not get the summer mpg. Tried all the trick (block heater. tires, running with heater off) I think it is just a fact you will drop 15%.
What I am doing is taking some readings on different points of my trip to work so I can compare them in the summer, and try to understand when the loss occurs.

The warm days will be back soon

ml194152 · 01-27-2008, 10:10 PM

My wife had a major front-end wreck with her Prius ($10K damage) and when we got it back, it was suddenly averaging only 35 MPG, whereas before she always got 45MPG (Houston, TX, summertime). We took it to the dealer and had them check about the gas mileage. They said they hooked up a meter to it and drove it 20 miles down the freeway and back and they said it was getting 37MPG which to them was "normal". So nothing was done. One month later I checked her mileage and it was at 45MPG.

I think you should just wait until summertime and see if it corrects itself. Winter is a killer for gas mileage, as everyone here will tell you. Even 60 degrees will reduce MPG from when temps are in the 90's.

01-19-2008, 01:37 PM	#1
popptj Junior Member Join Date: Sep 2007 Posts: 4 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Significant Drop In Gas Mileage I have an 07 Prius PKG 5 with 30K. The car has performed great up until now. Over the past week or two gas mileage has dropped into the 30's at times--38-40. I have not changed anything. Oil levels are fine, tire pressures are fine, etc. I notice that the battery stays green quite a bit...I read somewhere seeing a green battery is rare. I live in south Texas and it is cooler..but it's not crazy cold. Temperature has been in the 50's. Something isn't right. The electric/gas motor isn't coordinating as it should. To the dealership?? I can cruise at 60 and the meter is hanging in the 40's. Every now and then it will register higher mileage...say going down a hill or decline, but on level roads, nothing like before. Help appreciated.

01-19-2008, 01:39 PM	#2
Tideland Prius Moderator of the North Join Date: Oct 2004 Location: Canada Posts: 19,633 My Car: 2010 Prius Model: N/A Package: Technology Package (Canada) Thanks: 229 Thanked 346 Times in 245 Posts Friends: 23	Re: Significant Drop In Gas Mileage how long have you had the car? i.e. have you driven it through the cooler "winter" months? cause at 50°F, the engine will run more often.

01-19-2008, 01:49 PM	#3
DaveinOlyWA 3rd Time was Solariffic!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 12,378 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 24 Thanked 121 Times in 103 Posts Friends: 10	Re: Significant Drop In Gas Mileage hard to answer without location posted... many areas of the country recently went thru much cold than normal weather. are you in one of those areas?

01-19-2008, 02:02 PM	#4
popptj Junior Member Join Date: Sep 2007 Posts: 4 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Significant Drop In Gas Mileage Temperature is 60 degrees currently and still having the same problem. I am convinced something is wrong mechanically. I have heard about "flashing" the system at the dealer. Any thoughts on that or other potential fixes? I have driven it in similar weather before here with good results a month ago or so.

01-19-2008, 02:08 PM	#5
DaveinOlyWA 3rd Time was Solariffic!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 12,378 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 24 Thanked 121 Times in 103 Posts Friends: 10	Re: Significant Drop In Gas Mileage 60º.... ya, even if you drove like a maniac, you probably couldnt do worse than 40 mpg as long as you kept it under 70... i would have it checked along with tire pressures. my mileage took a dive once, more than 5 mpg... found out that had a tire down to 21 psi from 40... will say one good thing about LRR tires, they keep their shape well even with little air pressure

01-20-2008, 08:08 PM	#6
uncool Junior Member Join Date: May 2007 Posts: 14 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Significant Drop In Gas Mileage Im in the bitter cold of Chicago where my high 40s mpg are currently low 30s.

01-24-2008, 07:36 AM	#7
AOV Senior Member Join Date: Jul 2007 Location: Poughkeepsie, NY Posts: 303 My Car: 2007 Prius Model: Package: Base Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Significant Drop In Gas Mileage Winter and the heater is ruining my mpg's. Use to get mid to high 50's on a regular basis during the milder weather, now that it is 20's and 30'sF here, and with numerous short trips (less than 15 min. round trip) my mpg's are low 40's. Just came back from a 500 mile round-trip (highway mostly) and only got 45, used to get a lot more. I keep the cabin air at about 73 degrees.

01-24-2008, 08:28 AM	#8
gazz Senior Member Join Date: Mar 2007 Location: Coventry, UK Posts: 202 My Car: 2010 Prius Model: N/A Package: T4 Thanks: 8 Thanked 2 Times in 2 Posts Friends: 0	Re: Significant Drop In Gas Mileage Its colder in the UK and I have dropped from 65s to 55s. Does not matter what I do it just will not get the summer mpg. Tried all the trick (block heater. tires, running with heater off) I think it is just a fact you will drop 15%. What I am doing is taking some readings on different points of my trip to work so I can compare them in the summer, and try to understand when the loss occurs. The warm days will be back soon

01-27-2008, 10:10 PM	#9
ml194152 Senior Member Join Date: Nov 2003 Location: Katy, TX Posts: 120 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Significant Drop In Gas Mileage My wife had a major front-end wreck with her Prius ($10K damage) and when we got it back, it was suddenly averaging only 35 MPG, whereas before she always got 45MPG (Houston, TX, summertime). We took it to the dealer and had them check about the gas mileage. They said they hooked up a meter to it and drove it 20 miles down the freeway and back and they said it was getting 37MPG which to them was "normal". So nothing was done. One month later I checked her mileage and it was at 45MPG. I think you should just wait until summertime and see if it corrects itself. Winter is a killer for gas mileage, as everyone here will tell you. Even 60 degrees will reduce MPG from when temps are in the 90's. __________________ 2004 Seaside BC #9 (purchased in CA!)