03 Tahoe Z71 runs great, bad gas mileage.

[jwth]

I posted about a custom tune that brings about 24 mpg awhile back and recieved so much sh** from the experts that I had to laugh at ignorance, soo,
2003-Yukon-4X4 SLT
5.3l, 3.73 gears.
It is a custom tune I did at home with a HPTuners rig.
smooth out the VE table, pump up the timing until it knocks and then back it down a couple of degree's, get in and adjust the torque tables, adjust Wide Open Throttle ,
fuel trims,

 

[jwth]

You get out what you put in.
Do not knock it if you have not tried it.

 

[Brad Nelson]

24mpg is great! Especially with 4x4 and 3.73s. I have thought about HPtuners mostly to see all of my data, but I can’t seem to make sense of what it costs on their website. They have all these different accessories and packages and I have no idea what I need. I have tuned a couple of motorcycles myself so it is not totally unfamiliar territory.

I just took a trip last night and managed 17 mpg highway while keeping it mostly between 50-70. It seems to be improving. I had pulled the battery to reset the pcm when I first got it (fixing a rear ac issue). That has been about 8 tanks of fuel ago now. I figured it would re-learn after about a tank, but maybe it has just taken a long time.

 

[jwth]

You really can get by with the basic unit and you do have pay for the required credits to license your vehicle to the rig.
Lots of help there.
Been tuning cars and trucks for over 45 years and found HP Tuners to be the easiest.

 

[Bwhntr6]

Just had same symptom with mine was running a little on cold side replaced thermostat and coolant temp sensor now motor runs 210 degrees as it should. I would try sensor first since it easier.cooler motor temp tells computer to send more fuel

 

[swathdiver]

I posted about a custom tune that brings about 24 mpg awhile back and recieved so much sh** from the experts that I had to laugh at ignorance, soo,
2003-Yukon-4X4 SLT
5.3l, 3.73 gears.
It is a custom tune I did at home with a HPTuners rig.
smooth out the VE table, pump up the timing until it knocks and then back it down a couple of degree's, get in and adjust the torque tables, adjust Wide Open Throttle ,
fuel trims,

I think I remember; at what speed does she get 24 mpg? What mods have been done to the engine and drive train if any?

 

[jwth]

No mods
Stock 5.3l , 4x4.
I tuned it in the 1400 to 2600 rpm ranges. Worked out to handle from about 35mph to 75ish mph. Varies in the city depending on traffic but runs true with cruise locked in on the xway. This is my daily driver so I am careful of what I do.
This vehicle has over 200,00 on it and the plugs were changed at 125,000. No oil use, no knock, runs fine, pulls in towing for a small trailer fine. Uses regular at the pump.

 

[Pwrshft99]

As a newer owner of a 05 Tahoe, this was a good read. One suggestion I'd make is something I learned long ago, dont be afraid of being aggressive with RPM.

I drove an 5.0 Explorer for awhile and found that it got better mileage operating above 22-2500 rpm. When I putted around, thinking I was being efficient, it got terrible mileage. When I aggressively accelerated that coasted at speed, it did muuch better. Ive taken a similar approach with my Tahoe but havent really monitored fuel economy yet.


Also, depending on where you are located, winter gas is still around. Couple this with warming your vehicle up a bit in the cold and fuel economy can't be considered honest this time of year IMO

 

[Brad Nelson]

I live in Myrtle Beach, S.C. so winter gas is a non issue here. I still seem to be getting a dismal 12-13 mpg around town. It may be that my trips are mostly short and the engine never warms up. It may have to do with the thermostat or temp gauge as well. Unfortunately I have hit another rough patch in my life, so tweaking my 'Hoe will have to go on the back burner for the moment. I appreciate all of the help here, and I will be looking towards HP Tuners in the future.