normal truck bad gas mpg

clifford · September 3, 2005

hi please tell me how to get better mpg out of a 2004 2500 pickup with a 6.0 engine and a 4.10 rear

drumset5994 · September 3, 2005

With 4:10's and the 6.0 ...i would assume originally the gas mileage in it wouldnt be good.

Start with your basics...check the air in your tires (i know, stupid, but sometimes you may not notice 10 lbs. missing in a tire)...i would say plugs/wires, but you have a newer truck.

I do sympathize with you though...i went from a 96 S10 2.2L that was pulling 30mpg highway, to a truck that pulls 22-23 highway... although i cant imagine how much your truck sucks gas up...i am truly sorry.

I'm stumped...sorry

GM-Tech · September 3, 2005

hi please tell me how to get better mpg out of a 2004 2500 pickup with a 6.0 engine and a 4.10 rear

Ain't happenin' with that kind of vehicle.

The only tip I can think of is to drive like there's a raw egg between your foot and the gas pedal and you don't want to break it.

redvett · September 4, 2005

You bought a 3/4Ton HD that is designed to WORK and gas mileage isnt a requirement. If your using it to tow or carry heavy loads every day than you have to live with it.

vhato · September 5, 2005

I have an 2500HD Crew Cab, 6.0, 4.10, 4x4 truck w/245's.

My last Tankful was 16.8 MPG according to DIC. I drove a tad more than 385 miles on 23 gallons of fuel. Here is how I did it.

1. Enabled the hidden PCM's Lean Cruise for 55 MPH or more

2. Never exceed 2000 RPM when accelerating in any gear

3. Never exceed 60 MPH

4. Only run A/C when outside temps are at 90+ degrees

Sure it blows to drive so slow and Lean Cruise reduced higher speed HP and towing ability, but it saves money and my work commute is 57 miles a day both ways. If I need power, I will remove Lean Cruise. You gotta have tuning software to do it though

71GMC_3/4T · September 5, 2005

vhato,

How in the world can you not exceed 2000 rpm when accelerating? I've tried it, and my truck just seems to maintain the speed it's at and not shift up unless I'm going down a hill or something. I've got to push it to 22 or 2300 rpm to get it to get into the next gear.

You've got me wondering about this lean cruise tune thing. Is this something that can be programmed so it only activates in the tow/haul mode, or is it global? It would be sweet if I could turn the tow/haul mode into max-mpg mode.

vhato · September 5, 2005

vhato,
How in the world can you not exceed 2000 rpm when accelerating? I've tried it, and my truck just seems to maintain the speed it's at and not shift up unless I'm going down a hill or something. I've got to push it to 22 or 2300 rpm to get it to get into the next gear.

You've got me wondering about this lean cruise tune thing. Is this something that can be programmed so it only activates in the tow/haul mode, or is it global? It would be sweet if I could turn the tow/haul mode into max-mpg mode.

<{POST_SNAPBACK}>

My truck accelerates fine till about 55 MPH while maintaining 2000 RPM. The only thing I can figure is you increased tire size. I still have 245/75r16's. Going to 265 or 285's can change that. What else did you do? High Flow Intakes and Exhaust can reduce lower end torque also. Did you change those?

A tuned PCM can do all kinds of things for you. For instance, the basic tune reduces your Air/Fuel Mixture from 14.7:1 to 12.9:1. These Engines make MAD HorsePower and Torque running a tad richer. The Extra Power makes up for the extra fuel consumption, by getting you up to speed faster.

Tuners also make the High/Low Octane Tables more strict. As long as you run a good, quality 87 octane gasoline you will get improved performance here also.

GM tunes their PCM's and Mass-Air Flow Meters to be with 10%. My truck was off by 11-13%. PCM Tuners attempt to be within 5% and Dyno Tuners will be within 2%. Just by recalibrating the MAF in the PCM to match your Fuel usage gives you a 2-fold improvement. The first is in improved fuel efficiency. Your engine is probably bouncing between 10% rich and 10% lean. This is wasteful and a calibrated MAF fixes this. The second improvement is in throttle response. As soon as you stomp the gas, the engine will respond.

Lean Cruise has been with GM since OBD1. What it does is reduce fuel use by Leaning the mixture from 14.7:1 to as much as 17.0:1 for a preselected speed. The EPA would not allow its use because it increases Emmissions into the atmosphere. The resulting increase in temperature could also ruin Catalytic Converters. Tuners and/or Tuning Software can allow you to enable this option as well as set the thresholds for its use. I don't think it can be set to be used with/without Tow/Haul. You set the Enable Speed and Disable Speeds as well as reductions based on Engine Temperature, Time and Amounts.

71GMC_3/4T · September 6, 2005

Yeah, it's probably the tire size contributing.

I haven't done any other mods. I was running a PCM4Less tune, but I changed back to the original PCM to see if it really was helping. As far as I can tell, there was no difference for the tune. Still getting the same MPGs, if not better, with the old unit.