I have a 2002 Trailblazer 4.2 liter I-6 vehicle with a 4L60E trans., & a 3.73:1 axle ratio w/posi. I am wondering if an HPTuner could add more power & torque as it is a 10:1 CR engine & book says to use 87 octane which tells me that I believe this motor is severely detuned & could probably really benefit from a 93 octane tune. Also the trans. seems to hang in the lower gears quite awhile before upshifting unless I let off the gas which is not depressed very far to start with. Any ideas on some gains & to what approximate values would be very much appreciated. Thanks!