Mine has gone to crap. I'm at 78,000 miles or so and all was going well until about a month or two ago. The only things that have occured in the past two months are the throttle body cleaning & the rear axle inner seal replacement/new rear diff fluid.

Does anyone think the latter could have adversely affected my fuel economy? I've noticed a drop over the past couple months from about 17 mpg to about or just under 14 mpg. And I've been driving conservatively.

 

If you did the throttle body cleaning maybe you knocked some sensor wires? If you did, your computer could be getting some bad sensor data.

Also, you could have coincidentally had a oxygen sensor go out or something.
Any warning lights?

 

Another thing for you to consider;

In the winter time, most states mandate the use of oxygenated fuel to reduce emissions. As "green" as they are up your way, it would not surprise me in the least to hear that the rules are similar in Canada.

This stuff is infamous for it's negative effect on mileage and performance.

Check the pump and see if it has a sticker that says something to the effect of "This fuel contains up to 10% ethanol to reduce emissions". If it does, that might be your problem right there.

I am running about 4 MPG lower than I did in the Summer

Yet another reason to long for Spring

 

Thx for the replies. I was thinking O2 sensor myself, but no lights have come up. I'm getting the diffs changed to synthetic today and I've heard people have 5% improvements in fuel economy going with syn gear oil. Crossing my fingers bout that one. I just want syn gear oil, better fuel economy would be a bonus.

As for gas, it's quite possible but Esso would have to do it behind the scenes. There's only 2 places (Mohawk & PetroCanada) that boast ethanol and 'green' so if there's ethanol in my lines it's not intentional on my part hehe, but still possible.

I do notice that fuel economy in the winter is always worse however. I don't even warm up my vehicles or idle to stay warm. I just didn't expect a 3 mpg drop...ouch...

Al

 

Had a huge drop myself. Last tank (17 gals), got a whopping 167 mi. out of the tank. I DONT let the engine warm up too long anymore.

 

That was my exact thougt when I read your post. I have over 12 years of averaged monthly fuel consumption data for my '90 and even without the winter mix fuel, my fuel mileage tyically drops an average 1-2 mpg in winter (usually from early November thru early March). With the winter mix, figure on another 1-2 mpg loss, at least, plus crappy performance.

The winter mix caused so much screaming by consumers in this area that it's either not being used here or they've changed the formula.

 

My gas mileage is down about 2 miles to gallon.Its the winter blend gasoline.Every vehicle I've driven for the past few years gets less gas mileage partly the gas blend and also the longer warmup time till the engine runs more efficiently .

 

It's gotten even worse. This time though, I have been warming it up for a bit before driving. It's extremely cold out.

Last tank I only got 4.96km/L (11.74 mpg). Swapped the air filter, will try this for a while & get an oil change too. See if that helps.

Just wanted to share but ughh.. this is truly disappointing.

 

did i read that right? you only get 2 mpg? meaning you can only go about 36 miles before you have to fill up again? :eek:

edit: nevermind, i need to read the posts a little more carefully. haha. you meant you gas mileage dropped 2 mpg, right?

 

In your post you mention how cold it is. Until your engine reaches its hot operating temp, it will have a rich mixture. Since it is so cold, it takes longer driving time to get to that hot temp, hence lower gas mileage.

Interesting note: Its in the 50's today in Seattle and freezing in Florida!

 

OK, I should have made it clear I meant 2 MPG less.Occassionly I have a Senior moment .
On the weather comment I noticed it was warmer in Anchorage,Alaska than it was here in the Buckeye state a couple days ago.
THINK SPRING!!!!!!!!!!!!

 

*sigh* you guys and your 14-17 MPGs. *rubs his online magic lamp* I wish... I wish... I wish

 

Hello...I've got a 2000 Sr5 4runner, I did the deckplate Mod, but I haven't replaced the filter yet. Plan to do it this week, for the first time I got 300miles out of a tank - full to fumes. Plus more HP, its winter time here in Colorado. I definitely recommend this simple/cheap modification it was worth it..!!

 

Hey Raiderman,Tell us more details about your mod.Explain it simple as I'm an old man and some of my brain cells have gone south.LOL:rolleyes: :pat:

 

I doubt that a change to synthetic lube in th diffs is going to make any noticable difference. I did it more than a year ago and I can't tell the difference. I just feel better about it.

 

I feel that Yoda is correct. I don't think that we suffer from the winterization of fuels down here in Florida, but the cooler temperatures mandate a richer mixture. Over the last 2 years (since I've had my 4R), I've noticed approximately a 1 mpg decrease from late December through mid March. That's the "cold" season down here. But geez, the last time it snowed was nearly a decade ago!

That in itself is an interesting notion. Runner a richer mixture in efect, cools down the engine. However it does theoretically increase power. I guess it's the computer's way of trying to increase efficiency based on O2 readings.

Recall that O2 sensors usually work off of O2 diffusion through a ceramic material. Cooler temperatures increases air density and diffusible O2, thus increasing the amount of fuel that the air can "hold".

The only way (that I'm aware of) to properly lean out the mixture is the start full rich and lean out until a slight drop in RPM is noticed. From there about a 5% increase in fuel mixture produces a properly leaned air/fuel ratio.

One last problem is that we don't easily have that sort of control over our motor's operation. Piston driven aircraft do however. I'll pass on the $20,000 150hp motor's they use though!

Just some food for thought.

-Davis