i got a 96 2wd 4.3 w and i have only been getting maybe 250-260 miles per tank of fuel is this normal?...I just got this a few weeks back just seams a little low to me....thanks

 

A better way to check is to find out your mileage between fillups and divide that by the gallons purchased to get a miles per gallon figure.

Depending on condition of your vehicle and your tire inflation pressures can have an affect on gas mileage. When i purchased my 2000 Blazer 4x4 4dr LS i filled up with two tank fulls and looked at the mileage and it looked a little off so i checked my tire pressures and they were about 2-3pounds low when I inflated the tires to the recomended pressures on the door tag then my mileage improved by about 2mpg.

Also if the plugs, wires, cap and rotor are not in top shape you could be losing gas mileage. If your air cleaner is dirty or if you have a MAF sensor in the air intake passage after the air cleaner it could need cleaning.

Plus high mileage will also take its toll on gas mileage.

 

I agree. We really need to know how many gallons you are using over this span. It could just be that your fuel gauge does not read properly, ie. it reads E with 5 gallons remaining in the tank.

With my Bravada, I do not normally go more than 200 miles before I fill up, but I rarely go below 1/4 tank either. My bravada (like all 4dr blazers) has an 18gal tank, while the 2dr versions have a 19gal, IIRC. So if the gauge is working perfectly correct, at 1/4 tank, I should have 4.5 gallons left. I average 17mpg on my commute so I should be able to get a max of ~300 miles on a tank if I were to run it completely empty. Running it completely empty is not good for the fuel pump as the fuel in the tank serves to cool the pump.

So given the inaccuracies of the fuel gauge, and if you are pulling it down close to empty, 250-260 seems about right. That would translate out to be around 15mpg give or take, which isn't all that bad, but could be better considering the 2wd.

How many miles are on the truck and when was the last time it had a tune up. I also agree that everything should be checked. Tires being low can cause lower mileage. Alignment being off can affect mileage as well.

 

Once you have checked it all and have new mileage figures, start driving different. The largest amount of gas savings will always be in the way the throttle is used. Yours may sound average to the readers here, but they can do quite a bit better. I do think that checking the O2 sensor is a good idea. The factory has a 30,000 mile service interval on those and no-one changes them on a regular basis.

If you have odd noises in yand around your car that may affect the knock sensor, think about fixing those problems. A knock sensor is a microphone tuned to a certain frequency and will lower the timing and often performance of your cars engine, if it detects this frequency. Sometimes weak or "the cheepest gas in town" will cause lower performance (due to knock) that ruins mileage. Not a good trade.


One common or normal thing for many to do is simply drive with foot on gas till its time to use the brakes, why?? These cars will coast a mile and slow only a little. You know your own area very well. So take this example from me out of the country. I drive 2 miles to get to a stop sign. I know from every Chevy I have had, including the carbed ones, that most of the time, the engine doesnt even begin to warm till I get to this stop sign. (in summer) Yet the speed limit on this 2 miles of road is 55 and wide open is more normal for many folks. Why would I want to run a cold engine (choke on in the old days) all the way up to 60 or even 65 before hitting the brakes?? I seldom succeed in reaching 55 before lifting to coast to the stop sign.

Next stretch is 55 also, right after the turn. It goes for 1.5 miles before dropping to 45. If I pull out in front of that distant car approaching at 60 or 65, I will have to certainly use the throttle a bit. At least its almost warm now. But why do it. Is it important to save 30 seconds? Not if I left on time, it isnt. So I let a car or two pass me while waiting patiently and then pull out. Seldom reach 55 before lifting to coast into 45 mph zone.

Odd part of this trip is that each and every time I take it, the speed limits get lower at each and every turn. I could burn lots of gas just speeding into a LOWER speed limit. Silly and expensive.

Yes, I live in the country and feather the gas pedal, but mine averages 22 -24 miles per gallon. The 95 Jimmy that is. My 350 4v carbed one ton van (full of tools, ladders on top) used to get 15. It's often the way you drive, but yes, I also kept things tuned and clean. Both the 2.5 and the 2.8 do better and the 2.8 could be the best of the three if driven properly. A better combination has not yet existed for general purpose use.

BTW blazers and trucks like my jimmy have the best air in the world. Cold, even too cold lots of times. This costs a lot of money also. If its 75-80 and you're not attending a funtion or dressed in your best suit, is it really neccesary to run the air, or is it a habit??

 

^^^ VERY TRUE ^^^ on the driving habits.

With the hills around me, the best I can muster with my Bravada is the 16-17mpg that I'm getting. And that is with coasting to lights and down hills, heck, even up hills that have lights on the top. When I first started driving this route, I was getting 13-14mpg. Just by changing how I drive, I gained a solid 3mpg. With these gas prices, that's quite a chunk of change.

You also don't want to rule out bad gas as a source of poor mileage. I found that a few of the stations in my area produced lower fuel mileage in my Bonneville for some reason (same octane used from all of them). I floated around putting 3-4 tanks of fuel from each station in and recording the mileage of each tank. Weird, but different formulations result in different things. Surprisingly enough, my Bonneville likes the 10% ethanol (gasahol) fuel the best and gets the best fuel mileage with it on my commute.

 

lots of hills around here too.......and i hear ya on the driving habits.....i have pretty much grown up enough not to think it's a drag car and take it easy but also i get the same mileage with any octane and whether i'm doing 90 on the autobahn or 50 onthe back roads....so today i got ahold of a scanner and pulled PO141 so I guess i'll be ordering some O2's soon......bank 1 sensor 2 which one is that?

 

Your description of the code is correct. In general for GM vehicles, B1S2 will be the pre-cat emissions only O2 sensor. The early OBD2 (your '96) display the B1S2 sensor as the rear most sensor. Later (like my 2k) do not denote this sensor as B1S2, but as B1S3 as to line up better with the names and locations on other models.

For GM vehicles in general, you'll have B1S1 which will be the bank 1 (bank that has the odd cylinders - 1,3,5) and it will be the sensor closest to the head. B2S1 is the opposite bank and will also be the sensor closest to that bank's head. B1S2 will be the pre-cat O2 sensor and B1S3 will be the post-cat O2 sensor. Both B1S1 & B2S1 are for engine management, while B1S2 & B1S3 are for emissions monitoring only. B1S2 & B1S3 will have NO impact on fuel mileage.

To see where the sensors are, take a look here:
https://blazerforum.com/fb.asp?m=16692

On blazers, B1S2<=>B1S3. There really is no B1S2 location, but like I said above, they moved to standardize their naming later on in the model.

 

Hear you. Its interesting to know that the O2 is showing up. I have no way of knowing how long you may have owned car or last time any O2 sensors were replaced. But if you have one going out, i would do a complete changeout. Nice to know which one it is and a good place to start, but if you have no certain recollection of the last time they were all done, I'd get them out of there one at a time as time and budget permit.

Your transmission is another good place to get better performance while simply maintaining the existing car. Something as simple as proper lockup oeration is very important. Things like speed sensors can be OFF due to tire sizes and such. This can cause such things as early or late lockup. Early or late lockup can cause lockup to go on and off more than it should, not good for anything.

Good fluid is important. Proper fill levels ar more important. Temperature affects the tranny in more ways than one. Breakdown of fluid and again, if running COLD, it may well prevent lockup. The puter judges temp to lockup. A hanging OPEN thermostat or missing one can keep lockup from starting to function when it actually normally would.

Your 96 can be anylized to a much higher degree by an expert in the use of the proper testing equipment. If I were you I would do a couple of more things, like clean the intake and make sure the tune-up is up to date. Once I felt it was as correct as I (myself) could get it, I would take it to a dealer or other well versed shop to have a good solid readout, not just of problems, but of the whole engine performance.

Perhaps swartlkk can expound on this sort of testing. I dont know modern prices, but I am certain that its one of the best ways to keep things on an even keel.

 

I did just buy this blazer and I think they are the same ones GM put in them back in 96 with 114,000 miles......but I don't wanna put cheap ones in so I'm going to have to order them 2 at a time.....but if B1S2(pre cat) doesn't effect MPG then maybe I want to look else where....it has new delco plugs, wires, cap and rotors......first thing I always do to a car I buy.....and yes i gap then right.....The fuel spider thing was just changed right before I bought it as was the fuel pump, filter, and a few other things.....the tranny was rebuilt by a Opel tech that does all the vette tranny's around here so I think it is in good working order......and it shifts fine and durning the drive mode on the scanner it didn't note any non lock up or locking and unlocking issues......oh and it has stock size tires.......i'll figure the actually mpg next time i fill up.....I just have to convert everything from liters to gallons.....3.8 per right??

 

ok so I cleared the codes to see what came back and this time around i still got the o2 code but i also got po700 and po1100....700 is the tranny controler malfunction and 1100 the scan doesn't know what it is........any ideas what would set the 700 code? where is the tranny controller?......can you replace them?