Sudden drop of MPG

M

medfordhotrodguy

New member
I have an 04 Limited V8 4x4 103,xxx miles. It became my daily (40 miles/day all freeway @65mph) in August. I was getting 18-19 mpg on 87 octane. In October it started dropping. Now it's down to 13 mpg on 91 octane 12 mpg on 87. In May I changed: timing belt/pulleys, water pump, t-stat, spark plugs, exhaust(magnaflow catback, crushed the OE on a rock). I know we have a lot of ethonol here in Reno around E18 for the winter, but in the summer it's E10. Just looking for any ideas. I have hooked it up to my OTC Genesis and flowed everything. O2 sensors look great. Everything looks good. Just out of ideas.
Anything from you Toyota techs out there would be awesome.
Thanks
Jeff
 
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seized brake caliper?

I've replaced 3 calipers due to seized pistons since I've owned the truck. Each time it's happened mpg's drop due to the extra resistance.
 
medfordhotrodguy said:
I have an 04 Limited V8 4x4 103,xxx miles. It became my daily (40 miles/day all freeway @65mph) in August. I was getting 18-19 mpg on 87 octane. In October it started dropping. Now it's down to 13 mpg on 91 octane 12 mpg on 87. In May I changed: timing belt/pulleys, water pump, t-stat, spark plugs, exhaust(magnaflow catback, crushed the OE on a rock). I know we have a lot of ethonol here in Reno around E18 for the winter, but in the summer it's E10. Just looking for any ideas. I have hooked it up to my OTC Genesis and flowed everything. O2 sensors look great. Everything looks good. Just out of ideas.
Anything from you Toyota techs out there would be awesome.
Thanks
Jeff
Click to expand...

It could be, as mentioned, seized brake caliper. But I think it's just the crappy winter mix in the fuel. Doesn't hurt to check the brakes, let us know what you find out.
 
I agree with the poster above, it's the winter blend fuel. If you live someplace that sees temperatures get down into the single digits and below, the refineries increase an additive that makes the fuel evaporate more easily. While it works to help your vehicle operate in frigid temperatures, it has the side effect of reducing the energy per unit of gasoline.
 
I see you are In Reno. It gets pretty cold there.

Has your commute changed recently? Having a short commute and driving short distances will kill your mpg in freezing cold temps.
 
At least you guys just have it in the winter. Here in Colorado, they used to switch it out during the winter only, now they keep the 10% ethanol gas here year round. :(
 
G.I.G. said:
At least you guys just have it in the winter. Here in Colorado, they used to switch it out during the winter only, now they keep the 10% ethanol gas here year round. :(
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Isn't it more than just the 10% ethanol for winter mix fuel? I believe I see 10% ethanol fuel here year-round as well. I thought it was another additive that is used more in the winter months.
 
NJshadow93 said:
Isn't it more than just the 10% ethanol for winter mix fuel? I believe I see 10% ethanol fuel here year-round as well. I thought it was another additive that is used more in the winter months.
Click to expand...

I think they just up it to 18-20%, then drop it back down to 10 during warmer months. At least that seems to be what they do here in New England.

Edit: Maybe 18-20 is an exaggeration... it's probably a few % increase during the winter.
 
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This is going to sound odd, I recently noticed my MPG's dropping. Figured it was because I was stepping on it, then I realized I really wasn't doin alot of leadfoot driving.

Then I started having issues with my battery with the cold & all here in Colorado...battery would turn the motor but not with it sounding like it didn't want to. So then I took my battery in to get tested. Red Top Optima- and it was no good! So because of the 3 year warranty I was able to get a replacement. After I installed. the MPG's came back! With an attitude! So I'm not sure if this has any connection to the other but...that's my $0.02.

Hope you find a solution. Let us know.


Ian
 
Ethanol causing drop in fuel economy...

I too have seen a drop in economy after purchasing my 04 4th Gen Runner from the state of Utah. To my knowledge they don't run ethanol. I live in Oregon where we have 10 percent year round. When I first purchased the runner it was getting 17-18 in town. Now in town I get 14-15 mpg. When I can I do run the non ethanol fuel and it seems to help. Any thoughts? I have 140k+ on it and I run mid grade to premium always.
 
Guys, ethanol is way harder to start in the winter. They use less ethanol in winter blends for sure. E85 is cut to e70, makes tunes extremely rich.
 
Another 04 v8 4x4 here with a sudden MPG drop off. I track / log my miles with every tank of gas. Just over 2yrs ago my mileage dropped from 17-18mpg down to 11-12mpg. This drop was not coincident with any service. I did my front brakes AFTER the drop off and the caliper / pistons were fine. Are they running this cruddy blend year round here in SoCal? Barely breaking 200 miles on a tank of gas is kinda harsh.
 
rando said:
Another 04 v8 4x4 here with a sudden MPG drop off. I track / log my miles with every tank of gas. Just over 2yrs ago my mileage dropped from 17-18mpg down to 11-12mpg. This drop was not coincident with any service. I did my front brakes AFTER the drop off and the caliper / pistons were fine. Are they running this cruddy blend year round here in SoCal? Barely breaking 200 miles on a tank of gas is kinda harsh.
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yeah, that sucks big time...i do abt 250 to 280 on a full tank..driving around town.....still not haapy:evil:
 
earthrealm said:
yeah, that sucks big time...i do abt 250 to 280 on a full tank..driving around town.....still not haapy:evil:
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DEAR LORD! I was upset when I dropped down to 350 miles a tank as opposed to my initial almost 415 miles a tank. . . .

COME ON SUMMER BLEND!
 
wadle5 said:
DEAR LORD! I was upset when I dropped down to 350 miles a tank as opposed to my initial almost 415 miles a tank. . . .

COME ON SUMMER BLEND!
Click to expand...

No kidding! I'm at about 340 miles now and my low fuel light hasn't come on yet. Dash display says 25 miles range but my Scangauge says about 60.

280 miles a tank? That's what I got in my 3rd gen with it's 18.5 gallon fuel capacity (and one of the few things I didn't like, the other being the lack of power from the 3.4 compared to the 4.0.)

I'm going to remember this thread the next time one of the V8 owners out there says "go ahead and get a V8, it's only a couple of MPG lower than the V6.: :bump2:
 
rando said:
Another 04 v8 4x4 here with a sudden MPG drop off. I track / log my miles with every tank of gas. Just over 2yrs ago my mileage dropped from 17-18mpg down to 11-12mpg. This drop was not coincident with any service. I did my front brakes AFTER the drop off and the caliper / pistons were fine. Are they running this cruddy blend year round here in SoCal? Barely breaking 200 miles on a tank of gas is kinda harsh.
Click to expand...

I'm in San Diego. Just purchased 05 V8 2WD and getting 16.5mpg on the internal computer. Gentle driving, 50% freeway/50% town roads. Car has 46K mi. Runing premium Gas.
 
Check it by hand and see what it comes out at, the computer resuts aren't generally real accurate. I get 16 myself so you may be close.
 
Its the fuel. The ethanol has less power in it so when you replace gasoline with ethanol, you get less work out of it and therefore worse MPG.

Also, it is counterintuitive but higher octane gets worse mileage. If you can run 87 without pinging, run it.
 
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