Whats the average amount of KM or Miles I should be getting out of my 5.9 under average daily driving?

I just bought it, and just put my first full tank of gas in... wondering if Catalytic Converter needs to be replaced or not. Not currently Throwing a CEL.

 

What code?

Average seems to be around 12 city, 16 to 18 freeway.

 

If you drive with a lead foot like myself... 10-12 city, 14-15 highway.

 

I get 11.4 city manually and computer are same for me.

 

in my 5.9L with 208K i get around 11mpg city...BUT i get a consistant 19-20mpgs on the highway (cruise set at around 67-68mph)...ive traveled to maine a few times which is 284 miles...takes less then a half a tank, and i have a 26 gallon tank....but its ALL highway with not much stop and go..

By the way, since your new to the truck.....change your plenum...and check to see if you have the deathflash

 

I get about 16 mpg with 35's and 4.88's. That's quite a bit of stop and go. I think with the cruise at 60 I could pull 18.

 

them 4.88s must be treating you good

 

Unfortunately, you can't measure it that way. Only true way to measure MPGs is miles driven by gallons put in at the pump. The first half of our gas gauge goes by a lot slower than the second half... even after the needle is on "E", there is still about two to four gallons of gas left in the tank (call it an emergency reserve).

 

When the light comes on it's 6 gallons left. Yep them 4.88's are great. I went from 10-11 mpg to 15-16. I haven't gotten on open highway and set the cruise yet though.

 

I get anywhere from 10.4-11.2 city on my truck. Highway depends on how fast I am going. after about 68 MPH, it MPGs go WAY down. B7 about 3-4 MPGs!!!

A lot of factors depend on your MPGs.
1. How often is your truck in OD: if you have lots of stoplights/signs in short trips and hardly see OD or even 3rd gear you will be in the single digits.
2. Hills add to MPGs
3. Traffic is not good for MPGs
4. Extended cab is about 4-600 lbs more than crew cab. (4900 for my crew, 5500 for my ext)
5. 4x4 vs 2x4. Big weight difference and power going through transfer case kills MPGs. YES, even if you are not engaged in 4x4, the transfer case still spins.
6. Gearing.
7. Death flash and blown plenum.
8. Letting your truck warm up in the winter.
9. Fuel type (10% ethanol, or pure gas)

I used to get 8.9 MPGs on my truck before my mods for city. But I lived only 1 mile from work, and I had 4 stop signs and a big hill. I hardly got out of 2nd gear.