did GM do something to the engines in the blazers after 98?

i see all you guys getting 18 mpg and i am lucky if i get 14 mpg (just driving around, little bit of highway, and around town)

are there any reasons that i should be getting that low mileage...it has been like that since i bought it in feb of 05

 

Unplug your O2 sensors and see if it changes?

Do you have any codes stored? Autozone will scan them for free.

Ever replace the air filter? Lack of air is a significant reason for poor gas mileage.


And in answer to your question, no. You should be averageing better mpg then that.

 

ok so 1. i dont know what the 02 sensor is....is it the same thing as the mass airflow sensor?
2. i dont hav an autozone anywhere near me...would pep boys do it? how bout my regular mechanic?
3. i have cone filter on it that i wash once a month


and also.....all of the sudden i am leaking something really bad...i think it is coolant....any helpful hints?

 

first things first what colour is the fluid coming from the truck red tranny green coolent black oil
put some carbboard under the truck for the night then see where to go from there.

 

1. O2 sensors are located in the exhaust pipes, and don't worry about them for the moment. You provided more info that maybe the key.
2. Pep boys might, call them. Your mechanic should be able too.
3. Cone filter? as in K&N filter. If so, this may be your problem.

You have to oil it correct? Too much oil and it gets onto the MAF/MAP sensor. Have your mechanic clean the MAF?MAP sensor. The ECM relies heavily on the data from the MAF/MAP sensor to control the engine air/fuel mix ratio. Incorrect info from the MAF/MAP sensor would explain your horrible gas mileage.

And what Nomad said about the fluid leak.

 

I do not think that aftermarket oiled air filters effect MAP sensors and I do not believe that the CPI (or TBI) motors have MAF sensors like the newer SCFI motors do. I posted the same thing, but then saw the vehicle year...

 

ok.....so 1. i do believe that the color is red.....it smells almost fishy...but it is coming from the very front of the car....it almost looks like the radiator is leaking....so i dont kno how it could be tranny fluid
2. it is not because of the cone filter cause i got even worse gas mileage before i put it on

3. and i dont know what u r talking about with the CPI and TBI and SCFI

4. i am going to call my mechanic and pep boys to see if either of them check codes for free

 

Now that I see the year, your MAF sensor could be coated and degrading the mileage. A simple cleaning with sensor safe throttle body cleaner will take care of that.

I also notice that you have that cone filter just sitting out in the engine bay. Not good for performance. With the setup you have right now, a k&n drop-in for the original filter box will outperform it easily. The hot air is worse than the restriction of the filter box.

CPI = Central Port Injection (some'92-'93 and '94-mid'96)
TBI = Throttle Body Injection (early 4.3L up through '92-'93)
SCFI = Sequential Central Fuel Injection (mid '96-current)

Depending on the mileage of the vehicle, you have things like carbon buildup in the cylinders causing hotspots that intern cause detonation. Detontation is detected by the knock sensors which retard the timing causing the engine to run less efficient. A Seafoam treatment will help to remove some fo the carbon built up in the intake, on the valves, and in the cylinders

O2 sensors also get lazy causing longer swings from rich to lean and back again(even before causing a check engine light to be illuminated). This will cause the engine to run less efficient. Some have had luck spraying carbon cleaner on their sensors to 'revive' them. I have never attempted this before. The O2 sensors that aid in fuel delivery are the upstream sensors before the catalytic converter.

Overall, on my commute (80% @ 55MPH rest stop lights and 30-45mph) I get around 15-16mpg. On trips, I get a solid 18-19mpg with cruise set at 70-75mph.

Another thing to consider is the terrain you are driving over. Where I live, there is VERY little that doesn't have some decent hills to go through somewhere in the drive (even on the trips). The flatter the terrain, the better the mileage should be.

So if you are driving around town most of the time, 14-15mpg would probably be about right for our vehicles. Heck, the EPA fuel mileage rating for a '98 4x4 is only 14 city/ 18 highway. And we all know how good the EPA is at giving representative fuel mileage ratings, LOL.

 

how much do some of these things cost to do? cause i am not exactly rolling in money right now

 

my blazer's doin about 21 mpg combined city and highway