LS4 Buick is "surging" in overdrive

[ChibiBlackSheep]

Hi all,

My friend purchased a used 2008 Buick Lacrosse with an LS4. Whoever owned it before him really jacked up the tune on the car, so I was trying to help him fix it.

I compared to a known good tune from another friend's 07 Monte Carlo SS, and noticed a ton of differences. So I made as many adjustments as I felt comfortable making, and we're off. He said the car is driving much nicer now, but he is noticing a surge a few times on the highway. I'm looking through everything and can't seem to find out why.

Unfortunately I don't have logs of this surge, as he is 4 hours away and just let me know. Anybody have any thoughts of what it could be? Or see anything terribly wrong that I missed?

Thank you in advance!

Keane_ModifiedtoDevinsTune_v5.hpt

[5FDP]

I wonder if the surge goes away if you lets off the throttle and gets back on it.

Might be a TCC issue inside the transmissing. Those 4T65e HD's are problem prone in a way, been around them too much lol.

I compared it to a 2005 GXP tunes I have from doing a friends car and not much was different.

[ChibiBlackSheep]

I asked him to check his trans fluid, but this wasn't happening before the tune I don't think.

That's why I'm wondering if anyone can take a look, see if something doesn't look right