Shift before 4000 RPM (aka drive less aggressively, cheaper on gas too) and you should be fine.
Edit. One other thing you may want to consider checking is a plugged exhaust. A good cheap way to test is to remove the O2 sensors, in this order (and see if the performance improves). Uninstall Bank 2 lower (radiator side) to determine if main cat is plugged, reinstall Bank 2 lower and then uninstall Bank 2 upper (radiator) to determine if Bank 2 precat is plugged, reinstall Bank 2 upper and then uninstall Bank 1 upper (hardest one, close to firewall) to determine if bank 1 precat is plugged. You don't need to mess with bank 1 lower as bank 2 lower will also be a test of that issue too (if that is the issue). Negative battery terminal needs to be disconnected before uninstalling or reinstalling O2 sensors. Good luck.
