I have a 2004 trailblazer 4.2 4x4 with the 4l60 transmission. When I drive from a stop the suv hesitates to drive. The rpms go up normally but at 3500 rpm it takes 13 seconds to get to 20mph. Once I get to 30 mph the truck runs fine. Already replaced throttle body, throttle body sensor. Tune up, cam sensor. And it’s a brand new transmission it has me completely stumped considering there’s no codes at all and all gauges are normal. Any ideas?