Get very low gas mileage (14.4 mpg) on a 2004 Chevrolet trailblazer. Has 140,000 miles currently. Just did a complete tuneup almost a year ago. Any suggestion as to get better gas mileage?

check plug wires

You could try the old fashioned way of checking your mileage. Start with a full tank of fuel. Make a note of the total mileage on the vehicle. Drive the vehicle normally normally until the low fuel light comes on. Refill the tank to full and write down how many litres/gallons you put in. Next check your total mileage display again and write that down as well. From those numbers you can work out you fuel consumption.
Subtract you first mileage number from the current mileage number to get your total miles driven. Then it's Miles driven divided by gallons of fuel used.
As most European pumps measure in litres you'll need to divide the total litres you used by the number of litres to the gallon. Then you can divide the mileage done by that number.
*Note* The American gallon is smaller than the UK 'Imperial' gallon so make sure you use the correct one.
[ UK = 4.55 litres to the gallon (Imperial)].
[ USA = 3.78 litres to the gallon].

no- no recall on the fuel tank that cracks at the filler neck the following link are complaints about fuel tank that are recieved if you go to home page and enter trailblazer they give you the break down of the whole series of model and complaints as well as recall information they also list the TSB technical service bulletins
2004 Chevrolet Trailblazer Crack In Fuel Tank

is this calculated mileage or what the estimated mileage is showing on the dash. Have you checked to see what you get on just the freeway?

What are your driving habits like?

How is your tire pressure?

Do you make a lot of short trips?

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

The Fuel Economy of the 2004 Hyundai Santa Fe is listed as being 16 mpg in the city and 22 mpg on the highway.----------------------------------------------------------------------------------
Digiprog3 Odometer Correction Tool

estimate towards capacity versus miles,for example if you get 300 miles on a ten gallon tank then your getting 30mpg.you should on a 02 checy v6 probably around 24-26 hwy mpg,check odometer at next fill up.











TIM............

i find it hard tto believe you ever got 33 mpg,
but you can always install some new plugs ans air filter,

Hello there:
If you look at your owners manual it will tell you that it is recommended that you only use the 89 or greater octane fuel and any thing below this can damage the engine i have the same truck and i have dome a lot of testing with the different fuels and they are right if i spend the extra 5 or 6 cents to get the good fuel i get better fuel mileage along with following the a regular tuneup intervals and also keeping the tires properly inflated helps out a lot ok So try these easy steps and you will find out that you will start getting better mileage

sounds like one of the shift silinoids in the trans is on it way out i had the same problem a few years ago

Renew the coolant every 24,000 miles or 2 years which ever comes first.
If your battery is in good condition, there is no need to change it.