I feel like I have been trying to keep a light foot. I figue at leat out of the last month I could have gotten better than 250-270 miles per tank. As for my tune it is a Nelson tune. My fist tune was 87-89 dual burn with shift points firmed some and 60% TCM left. My second is a 89-91 dual burn shift points very much more and 80%TCM removed so I just dont know what the problem is. I would be happy to just reach 300 or a little over again.

 

The PCM learns mostly fueling. It will learn where and when it needs to add fuel or take away fuel to keep the stoich 14.7 ratio.

I think this is another one to chaulk mostly to the lead foot syndrome. It could possibly be in the tune though, but more than likely it's the foot or something else that caused a lose in MPG.

 

My city mpg stayed the same but my Hwy mpg went up

I get about 310 per tank w/ a mix of city/hwy and about 380 hwy. Thats with Texas Speed 93 tune.

 

Just out of curiousity, did your tuner adjust for the taller tires? If not, that will account for some of the difference.

LOL...I was wondering the same thing!

 

My turning is always custom, its called "Get out of my way"

I fixed it!

 

My mileage is improved with all my mods even the 3.90 gears didnt hurt. I am still gettin 19-20 mpg. Custom Turn haha.

 

As for my tuner which is Neslson yes he did take in consideration and adjusted for the bigger tires. I am hoping that he did do this which in my retune I reminded him again of the tires. I am currently running 285's on stock GMC wheels

 

I have tracked every tank of gas that's ever gone into my '02, along with periodic analysis of the gas mileage figures. With a Wester's 93 octane tune, I gained approx. 1 MPG around town and 3 MPG on the highway. I can provide the gory statistical details if anyone's that interested. I've seen two things that really seem to affect gas mileage:

1. A heavy foot (hard to resist that, though!)
2. The power required to overcome resistance due to aerodynamic drag increases by the cube of the speed you drive. It takes 25% more power to overcome air resistance at 70 MPH than 65 MPH.

I suspect some of the mileage "losses" are due to driving harder/faster with a new tune rather than the tune itself.