Change in MPG

In some places, I believe that the switch the gasoline over to a "winter" blend which can cause MPG to decrease. When spring comes around (finally :-), then the MPG seems to go back to 'normal'.

I am not sure if this is the cause of what you are observing, or not, but it sounds like it matches my personal observations also living in the 'Northeast' part of the US.

Hello.

I have a '99 Camry, which I've had since Feb 2004. I have noticed that the mileage is lower in the colder months (I live in Canada). Since I got the car, my average mileage is 28.85 MPG (yes, that's in US gallons), but in the winter time it's not unusual for that to drop to around 25 or 26 MPG.

My dad owns a '98 Camry, and has noticed similar drops in MPG in winter. I think it's more due to the cold weather than a problem with your car.

We see the same drop in all our vehicles when they switch to oxygenated gas every Fall. If you are using midgrade, try using regular

- the Camry four does fine on that if you don't have to climb tall hills regularly.

Could be a thermostat stuck open, does engine temp seem lower on the gauge or does it take longer to get heat. How old are plugs and wires, sticking brakes,

Do you seriously think that all of our cars develop one or more of the above problems at the same time each Fall, then cure themselves in the Spring...?

I use regular but I do spend a good portion of my commute going up. Mid grade would give me more juice up hill?

The engine temp seem to be where it normally is during winter, the brakes are newish but I don't know about the plugs or wires I have had the car only just a year so I assume they are may be on the old side..

Yes, because the knock sensor won't be telling the ignition to retard the timing as much. Under those conditions you'd probably get better mpg with mid grade.

The thermostat will keep the same temp winter and summer in normal driving. New brakes does never include calipers unless they are bad at the time. Its probably winter gas formulations, but who knows until you do tests.

Your car maybe running in good condition. Since the advent of cold weather, did you start warming your car more in the mornings and been using the heaters frequently. This may also add to the oxygenated fuel mentioned to decrease MPG.

Yes I do warm my car up more ( i start it and then get washed etc before i leave) and when I get up into the mountain I run the heater pretty good..

Thanks for the Advice, now using the midgrade and I get 1 1/2 more trips to work on my one tank

You're welcome. As a general rule you get better MPG with regular if the engine isn't being strained. If it is, you get better MPG with a higher octane gas.

It must be a short trip to work. I don't think I've ever seen a claim of more than 5% for the improvement of using premium (much less plus) in a car that can take advantage of higher octane fuel (not all cars can). Of course if your car was designed to run on premium and you are trying to use regular, the decrease on regular can be much higher than

5%. The only reason I can think of to use plus, is if you car spark knocks on regular and you need that slight (and I mean slight) increase in anti-knock performance offered by the plus grade.

I have a Nissan Frontier V-6. According the owners manual, Regular Fuel is recommended, but Premium will provide superior power and fuel economy. So I ran a test. I keep detailed gas mileage records and drive the same sort of pattern consistently. I ran regular for many miles until the engine was broken in, then ran premium for about 2000 miles, then regular for a bout 4000 miles, then premium again for 3000 miles, then back to regular. My conclusion was that premium did actually provide better fuel economy in that engine - around 3%. That was not enough to justify the higher cost of premium. However, it was obvious that the engine management system was able to take advantage of the higher octane by adjusting engine parameters (ignition timing, cam timing, etc.). I have run this experiment on several other vehicles that claim to be able to take advantage of premium and not gotten the positive results I saw with the Frontier. Since I got good results running premium instead of regular, I tried the plus grade. It did nothing. I got no increase in fuel economy at all. My conclusion was that Plus is a rip off unless you need a minor increase in octane to avoid spark knock. Around here regular has an AKI of 87, plus - 89, and premium - 93. If you really want an AKI of 89, wouldn't you be better off buying 10 gallons of regular and 5 gallons of premium?

Ed

Wrere any of the "other vehicles" cars like the Camry four, where you havr a very efficient but large four cylinder engine driving a mid-sized sedan with a high-efficiency automatic transmission? This car is more capable than most of taking advantage of optimum conditions. It's the only car its size that I know of that can average 34mpg in mixed driving. This number can be dramatically lower if conditions aren't optimal, though: step too hard on the gas when accelerating, use the wrong grade of fuel for the terrain, have a plugged air filter, and you can easily lose 4 or 5 mpg...