2003 2500hd 6.0ltr

[tubbedamx]

Hi I have a 2003 2500HD with 34000 miles,

I have owned this truck since it was new and it seems it doesn't tow like it did when it rolled off the showroom. In tow haul mode it doesn't seem to have the power like it used to.

 

I was told these trucks learn your driving habits and adjust timing and shift points accordingly. If thats the case is there a way to reset that back to the factory settings?

 

I have a hardtime believing that but I guess anything is possible...

 

Thanks in advance.

[r1byker]

I doubt it's the transmission "learning" your driving habits; that' wouldn't affect your available power.

 

Let me tell you my experience that'll take you down a different line of thinking. I noticed my '05 Suburban was hard starting; it would take a couple tries with the starter before it would start. I took it in and they discovered the fuel pump was bad. After they replaced the fuel pump I noticed three things; it started right up, a definite increase in power, and an increase in fuel economy by almost 20%. In other words, it was back to what it was like when it was new. I had never noticed the decline in performance because it was so gradual.

 

I suggest this because I have a friend with an '03 Silverado who had to replace the fuel pump on that truck, as well as on his sister's Chevy truck. It leads me to believe that there's a pattern here, but I haven't searched the threads to verify that.

 

Instead of transmission, I would start thinking in terms of fuel supply (clogged fuel filter maybe?), spark, and air (air filter clean?), which are the basic components of combustion, hence power.

[r1byker]

By chance, have you switched over to running fuel with a lot of ethanol? Ethanol has something like 30% less energy than gasoline, so using a lot of that would make it feel like you're down on power.

[tubbedamx]

By chance, have you switched over to running fuel with a lot of ethanol? Ethanol has something like 30% less energy than gasoline, so using a lot of that would make it feel like you're down on power.

 

I suppose that could be the case...

All the stations around here advertise "At least 10% enthanol". There is one station close to here that advertises "Real Gas" no enthanol. I think i'll start filling up there and see what happens. I have changed the fuel filter a couple of times as well as the transmission filter and oil.

 

I never thought about the fuel...thanks

[killergixxer]

I can tell you from my experiances that the ethanol blend not only affects performance but I've persoally noticed a 1-2 mpg decrease from using it! It might cost a little more but I completely avoid the ethanol now!