I have 2000 Limited and get worse gas in the winter than the summer around 200 miles per tank in winter and 230 in the summer.

I typically keep the windows down in the summer and only use the ac on really hot days. In the winter I keep the auto climate control on just about all the time.

The AC light on the auto climate control always remains on when the heat is on, does this mean the ac compressor is running the whole time even though the car is being heated.

Sorry if this sounds stupid but is it possible that the compressor is always running when auto climate is on? Or is there another reason I am getting worse gas mileage in the winter? Anyone else experience something similar?

 

I used to drive a Gas tanker for Chevron for 10 years and in the fall all fuel distribution switches to a winter blend gas you can read more here. That is probably where you are noticing your difference.

http://ask.cars.com/2009/02/whats-th...y-cars-pe.html

 

winter gas is a different blend, it has more additives to keep moisture out. and for some reason you get worse mileage with it. durring the winter my '98 3RZ tacoma gets about 14-15 MPG, 16.5 if i'm lucky. but in the summer, i get about 19-21 MPG. so its not your truck, it's the gas

 

My little bro is "kinda" right. Summer blend fuel has a higher vapor point, meaning it evaporates at a higher temperature. This helps the fuel stay stable, and not build up so much pressure in the tank. In the winter time, the vapor point is lowered, to allow for better combustion, but slightly worse mileage. At least, that's how I learned it in school, so if someone know's better, feel free to correct me.

-Edit- Just read this link, and it describes exactly what I was talking about.

 

When you have the heat on, it's probably running through the window defroster, which does force the compressor to turn on. 200 a tank is very bad mileage, like 13mpg. Do you drive with a lead foot? I would suggest you try a fuel treatment and some Seafoam in the intake manifold and see if that helps anything.

 

I get Awful fuel mileage in the winter. I stopped calculating because it just made me sad... But the combo of almost always being in 4x4 (lots of snow), lots of short trips, and everywhere you go in this town is up hill... Its terrible.

 

Little story--When i moved to Texas from the People Republic of California--I bought gas in many different states. Sometimes the gas i bought didnt have ANY notice that it was 10% ethanol. I assume thats because it was all gas. Long story short--Sometimes i was getting 23 mpgs' highway and other times 19-20.....

FYI--

 

Interesting. I always blamed my worse mileage to letting the vehicle set and warm up for 5-10 minutes every morning and evening

 

I normally get worse mileage in the summer due to the fact that I run the A/C a good bit. If the A/C light is on regardless of summer / winter conditions...then the compressor would probably be cycling on and off. I'm sure this is having some effect on your gas mileage. I never use the climate control in the winter or summer. Just set the temp to your preference and control the speed of the fan with the dial.

 

Don't forget that when its winter we let the truck idle and warm up longer then if it were summer. So that plays a small part in mileage being worse.

 

Don't forget that when it's winter it's colder!

 

In Phoenix Arizona I usually get worse mileage when it's 110 degrees out, with or without the AC.

I get better mileage and my truck runs alot better in the winter when it's cooler out. Elevation kills my truck though, driving around at 10k feet my truck was dog and got horrible mileage.

 

Cold air is denser therefore more fuel to keep the same a/f ratios.

 

Doesnt work though pardner--you would get more bang for the buck with less throttle.

Here is what i am thinking--Higher content of ethanol causes the engine to lean out....leaner makes the engine run a little warmer and ping a little easier (i know from experience here). Knock sensors pick this up and dial back timing (3k RPM and above is when the KS work). This information is used by the computer to determine what happens below the 3k RPM mark when the KS's are not working.

With retared timing you get less gasmileage--especially during light load cruising.

GOING BACK IN TIME--The vacumm advance/retard on a distributor is at it greatest advance at partial thottle and light load--i.e..greatly improving fuel economy. Now that is just the vacumm and not the mechnical advance.

When you mash the throttle the vacumm advance actually receives less vacumm and therefore retards, A/F Ratio richens and as the RPM's increase the mechanical advance takes over the job of advancing the timing.

So, what do you think?

 

Sure it works. You do get more bang. Haven't you ever noticed how your vehicle is a bit more zippy in winter?!