Can't afford to drive it

Here it is - November 4th... The gas stations have started their 10% blend of ethenol in the unleaded gas, and my gas mileage has bottomed out!!!
 
Last night, I filled it ($75) with Mobil regular unleaded. I made certain that it was full. I drove no more than 30 miles (and that's pushing it) and I have already gone through 1/4 of the tank!!!
 
I'm not letting it idle... I am not driving like an idiot... The A/C is off (so is the front defogger)......
 
What can I do to increase the fuel economy short of driving only down hills with the engine off???  If this keeps going on like this, I'll have to sell my 07 Tahoe for a Ford Escape Hybrid.
 
I really do NOT want to get rid of it. The Kelly Blue Book on it is $33,250.00. I still owe $23k on it!!
 
HELP

I think you need to make a trip to your dealer. The tank holds 26 gallons so 1/4 tank is 6.5 gallons which means you only got 4.6 miles to a gallon!!!  I get 13-14mpg towing a 3500 lb travel trailer for the last 9000 miles.

Did you go back and fill it up and then divide miles driven since last fill up by gallons used to refill tank?  You guage may be off.  Like the other poster stated 4-5 miles per gallon does not seem right.

Did you check your DIC?  Even E85 doesn't kill mileage that bad.

I feel your frustration with gas....in all 18400 miles on mine, i calculated that im only getting 12 mpg...and the sad part is that i would venture to say at least 12000 of them are on the hwy

That doesn't seem right...how many miles do you have on it?  Mine is right at 3000 miles and before taking a road trip two weekends ago that was about 500 miles, I was only getting about 11mpg in the city....now I am getting about 13mpg in the city.  4-5mph is ridiculous.  No way could the engine being using that much fuel.  Go back and fill it up again and see how much it takes to fill up....I bet the gauge is off or maybe you are sitting on an incline when reading gauge?  Sometimes when I am on an incline and read fuel gauge it reads low (due to location of float in tank and shap of tank)...

quote:

ORIGINAL: jlenkows

Here it is - November 4th... The gas stations have started their 10% blend of ethenol in the unleaded gas, and my gas mileage has bottomed out!!!

Last night, I filled it ($75) with Mobil regular unleaded. I made certain that it was full. I drove no more than 30 miles (and that's pushing it) and I have already gone through 1/4 of the tank!!!

I'm not letting it idle... I am not driving like an idiot... The A/C is off (so is the front defogger)......

What can I do to increase the fuel economy short of driving only down hills with the engine off???  If this keeps going on like this, I'll have to sell my 07 Tahoe for a Ford Escape Hybrid.

I really do NOT want to get rid of it. The Kelly Blue Book on it is $33,250.00. I still owe $23k on it!!

HELP

 
If your figures are accurate you have to have some problem (and with those numbers you would have had to have gotten a "check engine" code).  I have just over 10K on my year old 07 and it averages 18 mpg in 95% highway driving @ 55-65 mph on 10% ethanol the entire time (calculated - not DIC; DIC shows about .5 mpg higher than my calculations which I attribute to temperature differences when doing fillups). 
 
Are you saying you noticed the mileage drop off immediately after the ethanol switch over?

Besides, read the reviews on the Escape hybrids, they are terrible on mileage, better than a tahoe?  Sure, but not much better.

I have a similar problem in my 2003 Tahoe, the first and last 1/4 tanks give me a mpg of 9-10 mpg while the center 1/2 gives almost 16-17 on 85% city and 15% highway. It averages out to about 14-15 mpg but haven't been able to find anything that would be a cause as of yet.

Here in so California, we are paying 3.15 a gallon.  From the price of oil and the recent poor margins reported by big oil companies, i would expect to pay $4.00 or more in the not so distant future!  Perhaps $5.00 a gallon is not out of the question!!!

quote:

ORIGINAL: thdrill

I have a similar problem in my 2003 Tahoe, the first and last 1/4 tanks give me a mpg of 9-10 mpg while the center 1/2 gives almost 16-17 on 85% city and 15% highway. It averages out to about 14-15 mpg but haven't been able to find anything that would be a cause as of yet.

Are you saying that actual calculations show that or is it just an estimate based on how much the tank holds?

Based on actual calculations, getting about 65 miles on first 1/4 and about 100 on each of the 2nd and 3rd 1/4's. Had problem with fuel pump shortly after purchasing and thought that might have been the culprit, but wasn't so. Changed spark plugs...still no change. Different fuel (89 instead of 87)...no change. So I am at a loss for answers. Was wondering if it was suppose to be that way with such a difference in fuel efficiency. Any suggestions?

the good news is that even with the black book recovery you can still afford a Smart car. People don't typically buy full size SUV's like the Tahoe for the gas mileage or economy

Something is wrong.  See the dealer!
 
I get 16.5 mixed.  19.5 highway @75MPH plus.  I just got 16.5 on a 200 mile, hilly E85 trip.

sorry I haven't responded to the posts - I've been working some crazy hours.
 
The DIC is at 11.4 MPG average (I reset it to get a more realistic number). As soon as I can free up some time, I'll get it to the dealer.
 
Does anyone know of any software fixes to improve economy?? 
 
I'm going to let this tank go to E an then try gas from a different station (current is Mobil 87) like LukOIL, Getty, Hess, or Citgo.

Could just be a non-linear fuel gauge.  What's your actual miles driven divided by actual gallons purchased?

I average around 14-15 mpg (mostly "city" driving).

quote:

ORIGINAL: 73shark

Could just be a non-linear fuel gauge.  What's your actual miles driven divided by actual gallons purchased?

This what I was thinking