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Thread: 2016 GMC Canyon 3.6L LFX Tuning Questions

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    2016 GMC Canyon 3.6L LFX Tuning Questions

    Long time reader/researcher first time poster. Let me get this out of the way, I am a complete newb when it comes to tuning. I have been an application developer and I've been around cars pretty much my entire life so I know a bit about both. I would like to merge those two and perhaps, eventually, get some more professional training with this. Here goes with my situation:

    I purchased HP Tuners for my 2016 GMC Canyon to change the tire height to correct the speedometer. That worked out great and now my speedo is accurate again. While in there, I thought I would research how to improve the shifting with the 6 speed. Some of you may know the 6 speeds in 2015 and 2016 are notorious for poor shifting under partial throttle. Since I was long out of warranty, I did not want to bother going to the dealer for a reflash with the latest GM tune (which is supposed to correct the issue). I found a tune on one of the vehicle specific message boards for the same vehicle, same year, same everything. Before flashing any thing to my ECU, I compared the two to get a general idea of what it was doing. There were some smaller changes with the TCC settings and shift speeds. Additionally there are a couple of tweaks to the MAF frequency and VVT cam timing. I loaded the updated tune and wow what a difference. It is a vast improvement over stock. From both the shifting and overall performance. Before, it wouldn't hardly spin the tires in the rain. Now, it'll do that with the larger tires. However, there are two nuances I cannot figure out:

    1) Just off idle, from a dead stop, when slowly accelerating, the RPMs dip a little and then kick in and go. I have wondered if this is related to the tweaks to the cam timing or MAF? What doesn't make sense to me on the cam timing is the only change is to the WOT settings. So, I wouldn't think that would apply to the symptoms I'm seeing.

    2) 90% of the time, the transmission shifts great at all shift points. However, when rolling through a yield sign. Meaning, decelerating to the point of almost stopping but then getting back on the accelerator, part throttle, the transmission seems to get "stuck" in too high of a gear and won't go. If I tap the gas lightly, it will come around, down shift and then shift normal. Also, while exhibiting this symptom, it will hold the gear for what seems like forever (again still under part throttle). Which seems like it could be the shift scheduling. However, I just don't know.

    Attached is my tune for reference. I have gobs of logs but I don't know if they would help anyone as I'm not sure I'm logging everything that would be needed.

    Any help folks can give is appreciated as I am trying to learn.

    Thank you in advance,
    Pete