auto problem ?

I hope someone can give me some ideas on what to do. Heres my problem i have a 1996 s10 blazer a year ago i put plugs wires cap and rotor in. last summer new fuel pump and filter. now i was getting 16-17 mpg in the city up to about a month ago and now im only gettin 10mpg the truck still runs smooth starts great so i was just thinking crap fuel but i have changed to premiums and have tried four different gas stations. so if anyone has an idea id like to hear it especially with gas going back up its getting to spendy to drive. thanks for your help.

Do you let your truck idle to warm up now that it got colder?

I know just the cold weather and me letting it idle and warm up dropped my trucks mileage from 15mpg+- in town down to around 11. Just a thought.

Pete

The first thing you need to do is hook the truck up to a diagnostic tester. If there is a problem with the engine it will have tripped a code in the computer and the tester will tell you which one. If there is a fault recorded in the computer it will send the engine into “limp mode” which will reduce fuel economy.

I believe you can have it tested for free and various auto parts stores. I think Auto Zone is one of them.

Well mine seems to only get around 10 mpg no matter what I do with it.

But if yours used to be pretty good I would look at the simple things like an air filter being plugged.

I do let it warm up a little but i dont think it should be hurting the mileage as much as it is. I did have a code in it last summer wich was the second bank o2 sensor. we cleared that code and it has not come back on. some one told me that the vortex has to run right at 190-195 our it will get bad mileage. I have put three thermostates in to get it to run hotter but the gauge still reads undet that so i think its just temp switch out gauge not reading right.

Mine did the same thing I was getting 20-21mpg and now I’m down to 17mpg I checked every thing filters, tires, codes, and now I’m thinking it may be the gas,
I drive on average 40 miles one way for work, so I keep track of my mileage, and this started at that first big cold snap we had ,
I keep my truck plugged in so warm up time is minimal, so I know that’s not it

its weird im thinkings it is the gas but i have asked three other people and they say there still getting the same mileage. so im at a lost i guess.

I would suspect it is temp related. I have never heard of an engine going into “limp mode” I know transmissions will ??? It could very well be on oxygen sensor. They are critical in detecting how much fuel to dump in. I don’t know if 96 Blazers have this feature, but on newer Chrysler Jeep & Dodges, it will not go into full torque convertor lock, until the transmission fluid is x amount of degrees, which would affect more if you do alot of short trips. For reference, my truck will not go into lock-up for about the first 4 miles or so. Like suggested, get a free scan to see if it set any codes

big G

derf. get the ecm scanned for codes first! it could be numerous things. first 2 things that pop in my mind are o2 sensors like g said or a catalytic converter partially plugged!

My first thought was pressure regulator, mine went bad got great mileage and then poor, replaced it and now Im back to average.

Thats what im hearing from a couple area mecnanics is that its the fuel pressure regulator leaking. I might try that and see if thats it. Thanks for all the replys.

you do lose like 10 % of fuel economy with the temps under 40.. and then you need to take into account how much you idle your car to warm it up.. that’s lost mileage as well.