Anyone else experiencing bad gas mileage?

I have an o3 blazer and have never had worse than 14 mpg. Now down to 12, The last service the guy that parked the car used the parking brake and I was concerned it was dragging, all wheels freewheling, and a guy at the shop with an 03 is experiencing the same thing. I had a no start at 12 degrees, some heet and jumper cables finally got a start after an hour. Cranked well but it was like it was trying to start on one cylinder. Thinking gas line freeze and heet fixed it. No codes thrown, mechanic guys doublechecked. I had moved the car 5 feet at 2 below to accommodate an extra car in the drive and had a bad feeling about that. 20 degree today and still starting fine.
2 Below in the am predicted, so I replaced the end section of the block heater cord as I think it was trashed by bouncing around in the wind, and from no continuity, now continuity. Sure the block heater may work but scared by my first no start, and have the rental car companies on tap in case the car does not start to spring dear old mom from nursing home to assisted care after hip replacement.

Is gas going bad?


Please clarify something

You said you have a 2003 Blazer . . .

However, from your previous posts, I know that you actually have a 2003 Trailblazer, correct?

I don’t want to cause waves, but they are 2 entirely different vehicles . . . different platforms, different engines, etc.

My Cobalt XFE, rated 37 highway has seen 37 in nice weather with my usual, relaxed driving style. Now with winter gasoline and cold enriched fuel mixture starts it is running about 31.8, 86% of 37. For you 14 x .86 = 12.04 mpg, a pretty good match.

Cold weather will always decrease mileage. 14 down to 12 is minimal. Just cold weather.

Yes @db4060 you are correct, sorry as you corrected me before and I failed again, it is a trailblazer with the 6 cy 4.2 engine, I forget how different the animals are. ps I liked your comment!

I was particularly displeased at a no start condition, never failed before at 18 below even. Gotta blame water in the gas and I only use BP, Shell or mobil. Do not recall the last gas stop but sure seems like water in the fuel as heet seemed to be the fix.


Okay, let’s try the easy stuff . . .

How are your fuel trims? That data would let us know if the PCM is compensating for a lean or rich condition, etc.

As far as the parking brake dragging, how about putting the truck on jackstands and finding out?

Once on jackstands, put the transmission in neutral and spin the rear tires. If the parking brake is dragging, it should be fairly obvious

If you’re at all in doubt about the parking brake, remove the rear rotors and take a look. If the shoes are worn down to metal, you may have your answer

Come to think of it, who’s to say that one of your calipers or brake hoses isn’t faulty, causing the brakes to drag?

Like I said all wheels are turning free, pardon my ignorance but my trustable mechanics said could not pull rears and feared messing with something not broken, ie springs flying out etc. Now I am not sure but have to trust them at this point that all seems good, and don’t want to open a can of worms. Now I am not just anybodies idiot, I am my wifes idiot, but I had a really bad feeling turning the car off after moving 5 feet in sub zero, then it failed at 12 degree, the block heater cord was damaged by flopping around in the breeze, and it will be 14 degrees colder tomorrow. Sure I think the block heater is working now, but unsure if gas standards have changed. Filled 1/2 tank of mobil premiumjust for kicks.

No @Barkydog, you are not your wife’s idiot. You are her fool, just as the rest of us are our wives fools; just as it should be.

4 below block heater seems to be working, no more engine start fails, Sorry @db4690 I know not about checking fuel trims. How would one check that?


As for fuel trims . . . you need to have a scan tool connected to the vehicle

There are short term and long term fuel trims, but I’m not going to get carried away here

It lets you know how much the PCM is correcting for a lean/rich condition . . . a diagnostic aid, if you will

I’m really oversimplifying it, but it’s basically raw data which needs to be interpreted

btw . . . what kind of terrier is that in your user picture?

The dog was a critter my daughter found freezing in a snow bank in an alley while home for Christmas a couple of years ago. Cairn Terrier seems to be the closest match. The mech guys did a scan and found no stored codes, but must assume a higher level of analysis is needed for trims. Well this is a cold stretch of unprecedented proportions, and it appears 11 to 17 as highs for the next week with overnight lows colder than that. Can Autozone do that, my mech is a tpical auto engine analysis for $95, but like I said, they scanned for free, found no stored codes and basically gave the car a clean bill of health. @db4690

Or, wait till spring. My theory is, in winter there are so many variables working against you, unless you drive a Focus or a Corolla, don’t even check your mileage. In the winter, it’s just too depressing. I agree witha basic check, but if you can get it running fine, wait till warmer weather to worry about the mpgs.

It is running fine, probably will throw a little heet in every now and then, Happy New year to you and all the other viewers. Maybe we should turn this into a post of posters critters, I know you saw tis, it is the golden and critter playing, but if others missed it here ya go!

Could also be bad coolant temp sensor.

My gas mileage has dropped closer to 20%. Now the weather has been pretty lousy even by our low standards- low of -8 this AM- and I will admit I do more short trips in lousy weather. Bike a mile to the store? Not likely with a windchill of minus whatever. Unless there are other symptoms- CEL or rough running, I think it’s the usual suspects- different gas, lower tire pressure, longer to warm to normal operating temps.

A relative of mine adopted what he thought was a mutt from an animal shelter

But it’s either a Norfolk Terrier or a Norwich Terrier . . . no papers of course