Distance per tank

[Mirror]

4.2L, 90% hwy, 100 km/h to 110km/h, all flat road, no hills anywhere, no accessories, just me and the spare tire in the vehicle, regular 87 fuel, only idoling is really in the morning warming up the vehicle since it is -20C to -30C right now and no accessories. Gonna put cardboard on the grill this weekend to slow down the rad from being cooled to fast.
I live outside of winnipeg, manitoba, canada

 

[mcsteven]

100 km/h is a little more than 62 MPH. I'm usually 60 or less. Yeah, I'd try that next (cardboard).

 

[Mirror]

100 km/h is our normal speed slimit here for hwy

 

[chipjumper]

Mirror you definitely have an issue as it is been around -20 to -30C where I'm at too and I've been getting around 18MPG with about 90% freeway at over 75MPH. In fact, I just filled up yesterday and quick math netted me just over 20MPG but I've had to slow down to the 55-65MPH range due to blizzard conditions.

 

[Eric04]

It's been as cold here for the past week. I drive nearly all country roads on my daily commute, so stop and go, acceleration, and 4WD has been locked in every day. I still managed to pull 15 mpg out of my last tank. I get closer to 17 without winter variables.

*edit* 17 if I keep my foot out of it. Not always possible for me.

 

[Mirror]

I only use 4x4 if i absolutely need it, ir driving through 2 feet of snow

 

[Chickenhawk]

Winter gas, very cold weather (I am 20 miles east of you), some use of 4WD, plowing through a few snowdrifts and the increased use of ethanol in the gas explains most of your problem. Now add in that your cat converter is likely half plugged.

No matter how warmed your truck gets, all the other parts still have to turn and churn in very cold lubricants and you will likely not get more than 400 Km from a tank.

I would suspect your cat converter. Get it tested or drive another TB to see if yours is substantially slower when accelerating at highway speed.

By the way, the cardboard no longer works, even in Manitoba. All it does is prevent airflow and decrease your mileage. It was important when fans ran at full speed all the time, but it will do nothing with a properly working clutch fan.

By the way, is your fan working properly? It should run at a faster speed only for a few seconds after startup. After that, it just basically freewheels. Does it sound very loud for longer than a few seconds? Once warmed up for a minute or so, you should be able to stop the fan turning by carefully pressing against the outside of the fan housing with a stick or a rag while running.

We have two Trailblazers, and neither one runs the fan at all, no matter how cold it is. When the fan failed on our previous Blazer, it was obvious just from the noise. (It sounds like a jet engine and I could hear my wife come home from three blocks away.)

 

[Mirror]

It definitely quiets down after warming up a bit.

And i was able to stop it with a gloved hand. Almost birnt my finger without a glove.

 

[Mirror]

We may have figured out the bad gas milleage, when we go to try and fix the 4x4 again, we are gonna check all the brakes, the front tires are tight to turn when on a lift and I smelt burning brakes when i got home last night from the rear.

 

[Mirror]

Update: does fuel milleage reaaly change that much on these vehicles. I went from -20C at 11 mpg to +2 and -3 and get 16 to 18 mpg now.

 

[mcsteven]

Actually the colder air is more oxygen dense and I could imagine it eating up 0.5 - 1 mpg but not 5 - 7 mpg. But the air that much colder also makes all the other fluids more dense (transmission fluid, transfer case, differentials) and those too could lower your mileage. Still, I cannot imagine a 25 to 33% drop.

Thermostat? As notes, frozen/stuck brakes? Lots of possibilities.

 

[Mirror]

Thermostat is brand new. Front brake calipers are brand new but am going to get them checked anyhow

 

[Chickenhawk]

That sounds pretty normal. Those cold temps really suck the gas.

Have you had your cat converter checked? It may be partially plugged from the bad thermostat.

If you feel it is a bit sluggish when accelerating on the highway, then it should be checked. These trucks really motor, and you should be able to pass someone in seconds when you really step on it. They will easily pull to redline in lower gears.

Almost any good muffler shop can do a backpressure test. The best time to do this is just before you need to replace your front oxygen sensor. (They should be changed at every plug change - about 160,000 kilometers.) The reason is that it is much easier to remove by cutting off the wire and using a regular deep socket, then putting on the new one with the special socket after the test is done.

Backpressure should be 0 at idle, and no more than 1 or 2 PSI at 2500 RPM.

 

[Mirror]

Where is the front o2 sensor located exactly?

 

[Texan]

The front 02 sensor is located in/on the exhaust manifold on the I6 engine.

 

[Mirror]

Having a new thermostat, i noticed when i let my tb warm upnin the morning, sometime between 5 or 10 mins, the thermostat only gets half way to 100. But when i get driving then it climbs. Is this normal, my bonneville used to get to running temp at idle.

 

[Mirror]

Well i replaced my driver hub assembly again in order to change the broken speed sensor, it was cheaper then buying just the sensor. My gas mileage went from 10 mpg to 15-18 mpg. And after driving 6 miles i didnt smell burning brakes so i'm guessing my brakes were being effected by the broken sensor.

 

[gojeda]

19 MPG on a recent tank full, running 60 MPH on the highway, no A/C, about 80% highway driving.

 

[SnowBlazer]

I use Costco 91 Octane and average 200-250 miles to the tank. But my driving is about 30% highway, 20 % spinning wheels in snow, and 50% city.

 

[Eric04]

I've dropped to 240 per tank in recent weeks(14 mpg) with no change it driving habits other than extended warm up times. Subzero temps many mornings so I let it run nearly ten minutes before leaving. We should be out of that mess finally.

 

[redleg6]

usually around 270-280 in the colder months, but I also drive about 80 miles a day bcak and forth to work

hoping in warmer weather I will get up to almost 300 miles per tank

(would be nice if we could get a larger tank in the SWB models)

 

[Mirror]

I removed the disconnect, now i get 19-21 mpg on cruise at 62 mph

 

[BlazingTrails]

I am getting upwards of 380 miles per tank now. I am showing 21-26 hwy and 16 in town. can't believe the 4.10 made it better? makes no sense to me....

 

[Mirror]

4.10?

 

[BlazingTrails]

4.10?

4.10 SS rear axle. It had a 3.42 before and it seems that since the engine is seeing a lighter load at highway speeds it is getting better mileage? I figured it would be the opposite.

 

[Texan]

My TB with 3.42 turns 2000 RPM @ 70 MPH. What does the 4.10 turn?
Just curious. Thanks.

 

[littleblazer]

With the 3.73 I get like 2150 at 70, 2000 at 65. I'd guess about 200 above that since my dad's envoy with the 3.43 turns around 200 rpms lower than me at any given speed... so like 2250-2350rpms, some where in that range I guess.

And to contribute highest I saw was 21ish mpg in the summer with the ac on, about 80 degrees, that was highway, 150 miles with maybe 7 of them in town, no traffic light head wind, doing about 72 mph.

Edit: around town in the summer in literally traffic lights every 1/2 mile stop and go I get around 230 to the reserve, that's about 18 gallons, I've never gone past 19.5 to fill, I'm scared to.