Over the past few months I have made the following modifications to my truck. Now that I'm finished I get a terrible surging when I try to drive the truck with cruise control on. It's so bad that I just don't use cruise. Wouldn't be an issue but this is my daily driver, I have a 40 mile commute to work one way and I am spoiled to my creature comforts. Hoping someone else has experienced the same and has some pointers for me on how to correct this so I do not have to resort to changing back to the factory throttle body.
Specs:
2004 GMC Sierra 2500 4X2 6.0
Ported intake manifold
Ported and polished throttle body
Replaced factory air intake tube with Airaid intake tube.
Computer Tune modified afterwards to get best out of improvements.
The modifications I have made greatly increased throttle response and seems like the issue is the computer over compensates (or does what it would with stock set up) to try and keep the vehicle at a steady speed. So, with the increased throttle response, when the computer adjusts to maintain speed it is like hitting the throttle in prep to pass someone. Then the computer immediately backs out of throttle because it's more acceleration than anticipated. Then, because the truck is now slowing, it gives more throttle again basically causing the truck to "buck" or "surge" down the road (throttle on, throttle off, throttle on, throttle off, in little less than one second intervals). They guy who did the tune said he has never heard of this before and claims it can not be adjusted in the computer. Sounds to me like the throttle body needs a different stepper motor or the computer needs to be adjusted accordingly. I have put the factory, unmodified, throttle body back on the truck and the issues go away...that's an important piece of the puzzle.
I know, this is kind of a unique issue and no one may have any suggestions but I wanted to post it up just in case somebody had a suggestion to try that just might fix it. Also, if you know of a person who does tunes that I may be able to call and confirm what my guy is telling me, please pass along their info.
Thanks in advance gang. Looking forward to your feedback.
Specs:
2004 GMC Sierra 2500 4X2 6.0
Ported intake manifold
Ported and polished throttle body
Replaced factory air intake tube with Airaid intake tube.
Computer Tune modified afterwards to get best out of improvements.
The modifications I have made greatly increased throttle response and seems like the issue is the computer over compensates (or does what it would with stock set up) to try and keep the vehicle at a steady speed. So, with the increased throttle response, when the computer adjusts to maintain speed it is like hitting the throttle in prep to pass someone. Then the computer immediately backs out of throttle because it's more acceleration than anticipated. Then, because the truck is now slowing, it gives more throttle again basically causing the truck to "buck" or "surge" down the road (throttle on, throttle off, throttle on, throttle off, in little less than one second intervals). They guy who did the tune said he has never heard of this before and claims it can not be adjusted in the computer. Sounds to me like the throttle body needs a different stepper motor or the computer needs to be adjusted accordingly. I have put the factory, unmodified, throttle body back on the truck and the issues go away...that's an important piece of the puzzle.
I know, this is kind of a unique issue and no one may have any suggestions but I wanted to post it up just in case somebody had a suggestion to try that just might fix it. Also, if you know of a person who does tunes that I may be able to call and confirm what my guy is telling me, please pass along their info.
Thanks in advance gang. Looking forward to your feedback.
