Junior2gs

I have a 99 gs300 and when I first start the car and try to drive off the gas pedal sinks and it doesn't wanna go much. But once I turn off the car and turn it back on again it works perfectly fine. My check engine light is on for the o2 sensors but I recently changed out all my o2s with new ones so idk why it's giving out a code for that. Both vsc lights are on also so if anyone can provide me with some help I would greatly appreciate it thanks!