I have a '01 suburban z71 5.3l i recently purchased. Im curious what others that have or have had this year suburban get for an average mpg. I cant seem to get any better than 15.5. I would love to get 16.5-17 but doubtful of that happening. I have even tried a diablo tune and that has yielded me a mpg gain of a big fat 0. If i drive i like i stole it i get 15.25 avg. babying it i get the 15.5. as a side note i did do a tune-up after i purchased. I used a/c delco wires and a/c iridium plugs. I also seem to have a slight miss only at idle that i cannot figure out the cause.

 

Welcome to the forum...
If you have not already you may want to clean the throttle body, this won't so much help with MPG as it will with a better idle....
15.5 isn't too out of normal... make sure tires are inflated, that you are not carrying a lot of extra weight around in the back of the burb...
most mpg is lost on hard take offs, but in traffic that can be hard to avoid without getting run over..

 

thanks for the response. I have actually already cleaned the tb.

 

Do you know what rear end gears you have? that can also impact your overall MPG lower gearing (higher numerically) will decrease mpg....

 

I probably should have checked that sooner glove box code shows GT5 which comes back as -4.10 Ratio and G80- Locking differential Rear.

 

Those are good numbers to have if you are going to do any towing....

 

I just sold my 2001 Burb 4X4 with the 5.3, 4.10 axles and the locker.

Now, granted, I had a PCM tune (93 hot tune from Wheatley). And I usually drove it like I stole it - returned a steady 14-15 mpg whether it was city or highway driving.

A buddy has an 02 with the 4.10 axles, and he's claiming big MPG gains from his dual exhaust install. While I doubt it's the 2-3 MPGs he's claiming, I'm sure it helped.