Hey all,
I'm heading to the dyno in 2 weeks to get my project car tuned, its a SBC406 with AFR heads, HSR EFI intake, EX276HR cam, with a 0411PCM running it all with a stock 1997 4L60E, stock converter and 2.73 diff.

The tune LRT helped me with has been fantastic for idle and driving it around, there's a weird issue with a temporary bog-down and backfire spot, but that's not my issue.
My issue is when it is working nice, I'll put the foot down and the engine will rev great, but the transmission is flaring and not putting power to the back wheels.

I'm not sure what the transmission calibration is that was swapped in, but I'm wondering if there transmission calibration is for something meant to be a lot softer or slower changes etc, if someone can take a look.

The other issues I have that might/maybe affect it are:
* Possible vacuum leak causing the brakes to not work that great (could also be the issue with the backfire/bog down issue)
* Fuel sounds like it boiling back in the tank. After 20 minute drive the fuel is just bloating in the tank and you can hear it hissing and bubbling

Trans fluid is at correct level, there's no leaks or anything, and all gear changes are working and fast into gear at idle.

I just need to know if it's possibly a tuning issue or a problem with the trans before I lay out $1000 for a day of tuning to find the power won't transfer and they cant tune the engine under load.