Little help with horrible fuel mileage!!!!

[altereddezignz]

Ok everyone. Still very new to the game and i bought a 02 Silverado HD 4x4 6.0. This truck gets 9 MPG with new fuel filter, plugs, wires, air cleaner, brakes, u joints, no codes. Yes i did brakes just to make sure nothing was dragging and it needed u joints lol. Oh and fresh oil, rearend fluid and front end fluid, Trans flush and tfer case flush.

Pulling a trailer it gets around 7. Here are 2 logs. First log was just a drive up the road and 100% throttle for just a bit.
Second log was a from dead stop and pin it just to see. Yes these are probably not what your wanting but i have to start somewhere...

Also can someone please tell me how to save the stupid historgram where it shows when i look at a saved log?

combs 1.hplcombs 2.hpl

[altereddezignz]

Sorry just clicked on Histogram and clocked load all data and it is there now!!! Sorry ROOKIE mistake!!!!

[5FDP]

How many miles??

Original o2 sensors?? Front anyway, rears dont matter.


6.0's in heavy halfs or 2500's do suck down gas though. Or pos 1500 HD shop truck that we have at work gets 12 mpg in the summer and 8-10 in the winter. I'm sure if they lowered the torsion bars back down and took out the rear lift block and were back down to stock right height aswell as do new o2 sensors and plugs we might get 13-14 on the freeway. But it's not my truck and they dont like my advice haha, it's a hauler and plow truck keeps running with 188k.

[altereddezignz]

How many miles??

Original o2 sensors?? Front anyway, rears dont matter.


6.0's in heavy halfs or 2500's do suck down gas though. Or pos 1500 HD shop truck that we have at work gets 12 mpg in the summer and 8-10 in the winter. I'm sure if they lowered the torsion bars back down and took out the rear lift block and were back down to stock right height aswell as do new o2 sensors and plugs we might get 13-14 on the freeway. But it's not my truck and they dont like my advice haha, it's a hauler and plow truck keeps running with 188k.

I'll have to look again I think like 195. Yes pretty sure the originals.

[Ranger6202]

you're Long term trims don't look too great (adding %10) . Something has changed in your setup to where it's adding fuel. I'm with 5fdp, you might want to change o2's depending on their mileage. Either you're requiring more fuel because you're flowing more air or because your fuel system isn't flowing the same as normal, or your A/F feedback (o2's) are reading differently than normal (drifted calibration).