Not 5.3 but 3.7 engine, 2009. Used HP Tuners to set upshifts and downshifts to where I wanted them. It's a process; I think it took four or five tries setting up the tables until I was happy with the results. Nikal, I hear you. Too early upshifts. On long uphills and I hated having to keep pressing harder and harder on the accelerator while losing speed until the transmission finally downshifted, resulting in an almost over-rev and all the noise and fury that the 3.7 could muster. Now, when I start to lose speed on a grade, I can downshift with a slight increase in throttle. I also tightened up the torque convertor lockup. Instead of gradually ramping up the torque convertor duty cycle I have it set to start at 80% duty cycle. Not a harsh lockup, just feels like another shift point. I want to stress that I didn't mess around with shift pressures, just timing!
After getting the transmission program where I wanted it I lost all desire to mess with engine timing or fuel tables. Not needed in my opinion. Hard to explain but the engine seems to be in it's happy spot all the time. Mileage is unchanged.
I also tool the opportunity to delete the VATS and bump the idle speed in Drive from 600 to 650 RPM. The imbalance in the 5 cylinder is much less notable when stopped in gear and I haven't noticed any excess creep when releasing the brakes.
Jeepwalker - no dice on the TPMS. It's controlled by the BCM and to my knowledge nobody has a program to go in and change settings. Bummer, I could go crazy in there.
