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1996 Tacoma 4X4
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54 Posts
Discussion Starter #1
It has been cold here for the last month or so(-20C/-5F). I know milage generally suffers during winter months but I have lost 6 - 7 mpg compared to my summer milage. I was wondering if anyone has any pointers or past experiences that could make any improvement, thanks.
 

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Offical TN Hillbilly
2002 Silverado
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1,757 Posts
Keep your foot out of it? There are a lot of things at play that are impacting "milage". Usually it is measured by tracking miles traveled on the ODO and how much you pump into the tank. When it is cold like that you have longer warm up times, snowy conditions that come with winter mean you are driving at lower speeds for longer periods of time, traffic gets worse meaning more stop and less go time. All of this is time the engine is running and your ODO isn't racking up the miles. That leads to the impression that your milage is worse that it really is.
 

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1996 Tacoma 4X4
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54 Posts
Discussion Starter #3
I definatly agree with you on all points, but in my case only the longer warm up times are applicable(I'm comparing milage with a few weeks without snow to summer milage). I have a remote starter so I let it idle for 5 - 7 mins in the morning, less than a minute in the evening because I can't start it with the remote from where I work. But that 5 - 7 minutes is at a high idle with some sort of choking or at least it seems like a richer mixture, you can smell the fuel in the exhaust for a minute or so. Also I guess eveny thing is a little harder for the engine to move/turn when its that cold.
 

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2002 toyota Tacoma
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906 Posts
Ok here is my question for you are you staying in 4x4 Hi? becasue if you are it will suck the gas down. I live in colorado and we have had our share of snow this year and everytime I drive in 4Hi I loose abour 6 to 7 miles to the gallon. Hope this helps. when I put it back in 2wheel drive I go back to 19 and 20.
Are you using the etc button on? If you are taht will decrease your MPG.
Lance
 

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1996 Tacoma 4X4
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54 Posts
Discussion Starter #5
No, 2Hi bare highway driving, the snow this year has been coming in waves every couple of weeks. Generally here the temp comes up close to the freezing mark so I don't see a big difference in 4x4 vs bitter cold milage, both are bad.
 

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1996 Tacoma 4X4
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54 Posts
Discussion Starter #6
........Generally here the temp comes up close to the freezing mark during slow fall.......
 

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2002 toyota Tacoma
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906 Posts
When did you last have a tune up, plugs and such and what kind of oil are you using go to a full synthec if you are not using it now.

Lance
 

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1996 Tacoma 4X4
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54 Posts
Discussion Starter #8
I run 5W30 stuff from Canadian tire(which is Esso, which is exxon mobile), in the other 3 seasons I add a half bottle of lucas. I had a plug go bad on me this fall so I changed all of them. One thing I've been meaning to do if clean all the sensors in the intake. I have a K&N air filter and I read a post about the oil from the filter possibly gumming up the sensors, none the less the milage has suffed considerably since the cold weather hit.
 

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^Why are you warming up the truck? You don't need to do that with Fuel-injected vehicles. It's better to start driving slowly after you get oil pressure established. I keep it well under 50 MPH for the first couple miles, then drive normally.

The main reason MPG drops in the winter is not usually due to driving habit, but more because of physics. Cold air is more dense than warm air, and since FI engines mix air/fuel via a constant ratio, they use more fuel per RPM with cold air. Your engine puts out more power in the winter as a result. (Side note: I had fun seeing 33 MPG or so with my Taco years ago when I did some driving through the mountains in summer. Didn't have much power, of course.)

C
 

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2002 toyota Tacoma
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906 Posts
cleaning all the ports and the throttle body is a good idea aswell as the air filter and maf sensor. Make sure the ports to the egr are not clogged while you are there as well.

Lance
 

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C-5 Mekinik
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237 Posts
Keep in mind, that at colder temps and -5 is definately cold, the engine will run rich much longer than it does at say 60 degrees. This is whether you let it sit and warm up or not. Have you had this vehicle for a few years or is this your first winter with it? On my 02 (first winter with it), I have lost about 2-3 mpg and it only gets down to the high teens here.
 

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1996 Tacoma 4X4
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54 Posts
Discussion Starter #13
This is my 4th winter with it, I noticed this before but this is the first winter I've been a member of Toyota Nation and this is by far the most traveling I've done in the winter with it since I've had it. I could do without warming it up, but the main reason is to get some heat comming out of the vents and to deforst the windshield. I could tough it out and scrape the windshieild and idle it for a minute or so to get the oil pumping before I take off. But the air to fuel ratio makes sense, but what the function of the oxygen sensor? The volume of air dosen't change just the oxygen content per cubic foot raises. With the same amount of fuel and more oxygen shouldn't you have more efficient combustion? The same milage with more performance? Based on past exerience I know my therory is wrong but could some one explain it to me?
 

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C-5 Mekinik
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237 Posts
The volume of the air coming into the engine does not change, but teh density of that air does. The O2 sensor is for closed loop operation. Your engine does not enter closed loop operation until a set coolant temperature and time above idle.

A denser air charge with a corresponding jump in fuel will give a performance increase, but to really see it on an everyday street engine you would have to be on a dyno.

You also have to factor in that every other component and fluid in your drive train is at -5 degrees and will have a greater resistance to moving even if you are using synthetics. Synthetics do flow easier at cold temperatures, just not to the same extent as regualr oils. So, not only is your engine running richer longer, it has a higher work load to move the cold tranny fluid / xfer case lube / axle oils / grease in the wheel bearings / etc too.
 

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03' Matrix XRS 6sp
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And don't forget the winter blend fuels.
 

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Joe
2005 Hilux Tray Top
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270 Posts
winter economy

I know we don't get as cold as you guys here, actually its around 45 degrees C at the moment, but the coolant thermostat is very important and check your operating temperature with a independent gauge and see if its getting above 70 C because thats when the management system starts to lean off the fuel mix. I have fixed many high fuel consumption problems by checking the thermostat.

Good Luck from the sunny and extremely hot at the moment South Australia

Joe
 
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