My 2005 has begun to take a MPG hit

RadGash · 12-02-2007, 08:25 PM

I am no stranger as to HOW to drive a Prius. With that said, I wanted to ask if anyone else out there have taken a MPG hit on their older Prius? And mainly, DO YOU KNOW WHY? I know all about the sweet spot on the pedal, etc. coasting, being pro-active with traffic observation, etc., but that just doesn't seem to be as sensitive anymore. I now average 35mpg in town and 44 on the freeway even when I drive like a Prius Saint... WTF? Do you think the battery is dieing out? Does anyone have any clues to this? My friend passed on "hear-say" that a friend of his had this happen and he took it into the dealer and they "did something" to fix this problem... anyway, I thought I'd ask. Your input is appreciated.

firepa63 · 12-02-2007, 08:40 PM

The only MPG hit I've taken with my 04 is cold weather related. Have you checked your tire pressure and oil level lately? Low tire pressure and high oil level will reduce MPGs. I doubt that you have a traction battery problem with an 05.

catsbox · 12-02-2007, 09:09 PM

I will second that. When my MPG drops, I first check the tire pressure, then remember the cold weather means a drop in MPG.

**TonyPSchaefer** · 12-02-2007, 09:35 PM

Where are you located? As winter approaches, the Prius engine and catalytic converter will cool down considerably faster. When they get too cold, the ICE will run just to generate heat and warm them up. Of course, this will ruin your mileage. For a graph showing the correlation, click the link in my signature.

Nuevo Mexico Prius · 12-02-2007, 09:52 PM

Quote:

Originally Posted by TonyPSchaefer

... As winter approaches, the Prius engine and catalytic converter will cool down considerably faster. ... For a graph showing the correlation, click the link in my signature.

Very impressive stats Tony and nice MPG figures you have been posting lately. I have not gone to near the detail in recording as you, but I too so as much as a 4 to 5 MPG hit in cold weather in our '05.

sandra · 12-03-2007, 12:10 AM

My MPG went WAY down 20%+ when I changed tires. I replaced them with the recommended tires and pressure and had a tune up (have 45k miles on my '04) and it's still really bad. I used to get close to 50. Anyone have any ideas????

F8L · 12-03-2007, 12:46 AM

Have you guys done the obvious comparisons with respect to temperature, fuel formulas, road surface changes etc.?

Have the streets or highways on your normal commute been repaved?
Are you doing long-term calculations regarding temperature?
Have you tried switching from your normal gas station?

Sandra, what tires and size did you replace the Integrities with? What pressure are you running them at? Have you done any other mods that would add weight or suck up battery amperage?

I have an 05' Prius and because of my mods I was only averaging 44-46mpg (75-100deg temps). I swapped back to the stock tires/rims and took out the extra weight of my subwoofer boxes and now I am getting and average 52mpg over the last 5 tanks or so despite temps dropping to the 30s-40s.

sandra · 12-04-2007, 12:31 AM

I bought the Potenza G 009 which is what both the dealer and tire store recommended. When my milage went down so much I went back to the tire store and had them fill them to the max, which they did. I checked with Toyota and they concurred that the tire pressure was good (highest possible). I'm at a loss and wondering what else I can do. Last tank I only got 40 mpg and I'm driving in the same areas and I'm in N. California, so the weather's not an issue (besides, this started last summer). My driving style hasn't changed either, I drive it really conservatively (using the engine to break, am really good about gliding to lights and stop signs etc) Any suggestions would be welcome.
Thanks,
Sandra

F8L · 12-04-2007, 12:47 AM

Quote:

Originally Posted by sandra

I bought the Potenza G 009 which is what both the dealer and tire store recommended. When my milage went down so much I went back to the tire store and had them fill them to the max, which they did. I checked with Toyota and they concurred that the tire pressure was good (highest possible). I'm at a loss and wondering what else I can do. Last tank I only got 40 mpg and I'm driving in the same areas and I'm in N. California, so the weather's not an issue (besides, this started last summer). My driving style hasn't changed either, I drive it really conservatively (using the engine to break, am really good about gliding to lights and stop signs etc) Any suggestions would be welcome.
Thanks,
Sandra

What area do you live in Sandra? I'm in Norcal as well and my milage had never been great due to the speeds we are usually "forced" to drive or the weird commute in some areas.

Tires can make a pretty big difference. I swapped mine back to stock and my milage shot up despite lower temps.

sandra · 12-04-2007, 11:27 AM

I'm convinced it is not my driving style, road changes or weather that's causing the diminishing mpg. Is there anything I can do to the engine? Have you heard of this before? When I talked to the dealer, he told me a mechanic at the store had the same issue with the tires. Do you think I should switch out my tires? That seems really wasteful (and expensive) as a fix...

12-02-2007, 08:25 PM	#1
RadGash Junior Member Join Date: Jan 2005 Posts: 24 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	My 2005 has begun to take a MPG hit I am no stranger as to HOW to drive a Prius. With that said, I wanted to ask if anyone else out there have taken a MPG hit on their older Prius? And mainly, DO YOU KNOW WHY? I know all about the sweet spot on the pedal, etc. coasting, being pro-active with traffic observation, etc., but that just doesn't seem to be as sensitive anymore. I now average 35mpg in town and 44 on the freeway even when I drive like a Prius Saint... WTF? Do you think the battery is dieing out? Does anyone have any clues to this? My friend passed on "hear-say" that a friend of his had this happen and he took it into the dealer and they "did something" to fix this problem... anyway, I thought I'd ask. Your input is appreciated.

12-03-2007, 12:10 AM	#6
sandra Junior Member Join Date: Apr 2005 Posts: 5 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Mpg My MPG went WAY down 20%+ when I changed tires. I replaced them with the recommended tires and pressure and had a tune up (have 45k miles on my '04) and it's still really bad. I used to get close to 50. Anyone have any ideas????

12-03-2007, 12:46 AM	#7
F8L Collecting Data on Nature Join Date: Aug 2006 Location: Sacramento, CA. Posts: 3,997 My Car: 2005 Prius Package: #4 Nominated 1 Time in 1 Post TOTM Awards: 0 Friends: 15	Have you guys done the obvious comparisons with respect to temperature, fuel formulas, road surface changes etc.? Have the streets or highways on your normal commute been repaved? Are you doing long-term calculations regarding temperature? Have you tried switching from your normal gas station? Sandra, what tires and size did you replace the Integrities with? What pressure are you running them at? Have you done any other mods that would add weight or suck up battery amperage? I have an 05' Prius and because of my mods I was only averaging 44-46mpg (75-100deg temps). I swapped back to the stock tires/rims and took out the extra weight of my subwoofer boxes and now I am getting and average 52mpg over the last 5 tanks or so despite temps dropping to the 30s-40s. __________________ 2005 Prius California Rangeland ConservationCoalition Ranchers, Environmentalists, And Agencies Working Together For The Benefit Of All.

12-02-2007, 08:40 PM	#2
firepa63 Senior Citizen Join Date: Jul 2005 Location: SE Pennsylvania Posts: 436 My Car: 2009 Prius Package: #5 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	The only MPG hit I've taken with my 04 is cold weather related. Have you checked your tire pressure and oil level lately? Low tire pressure and high oil level will reduce MPGs. I doubt that you have a traction battery problem with an 05.

12-02-2007, 09:09 PM	#3
catsbox Senior Member Join Date: Apr 2005 Location: Bellevue, WA Posts: 254 My Car: 2005 Prius Package: #6 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I will second that. When my MPG drops, I first check the tire pressure, then remember the cold weather means a drop in MPG.

12-02-2007, 09:35 PM	#4
TonyPSchaefer Ruler of Omicron Persei 8 Join Date: May 2004 Location: Far-North Chicagoland Posts: 8,641 My Car: 2004 Prius Package: #9 Nominated 4 Times in 2 Posts TOTM Awards: 0 Friends: 18	Where are you located? As winter approaches, the Prius engine and catalytic converter will cool down considerably faster. When they get too cold, the ICE will run just to generate heat and warm them up. Of course, this will ruin your mileage. For a graph showing the correlation, click the link in my signature.

12-04-2007, 12:31 AM	#8
sandra Junior Member Join Date: Apr 2005 Posts: 5 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I bought the Potenza G 009 which is what both the dealer and tire store recommended. When my milage went down so much I went back to the tire store and had them fill them to the max, which they did. I checked with Toyota and they concurred that the tire pressure was good (highest possible). I'm at a loss and wondering what else I can do. Last tank I only got 40 mpg and I'm driving in the same areas and I'm in N. California, so the weather's not an issue (besides, this started last summer). My driving style hasn't changed either, I drive it really conservatively (using the engine to break, am really good about gliding to lights and stop signs etc) Any suggestions would be welcome. Thanks, Sandra

12-04-2007, 11:27 AM	#10
sandra Junior Member Join Date: Apr 2005 Posts: 5 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I'm convinced it is not my driving style, road changes or weather that's causing the diminishing mpg. Is there anything I can do to the engine? Have you heard of this before? When I talked to the dealer, he told me a mechanic at the store had the same issue with the tires. Do you think I should switch out my tires? That seems really wasteful (and expensive) as a fix...