I think your seats lift from the front.

This O2 sensor write up should be close. https://www.gmforum.com/t278913/

I don't suggest you doing any trans work unless you know what your doing. If you just bought the car this should have all been taken care of.

Yea they claimd to have done a tune-up and oil change and when I saw that oil I was pissd. I'm goin to do jus wat u said tho go head n have them ride n the car with me but one thng I can say is I had put sum of dat Lucas gas cleaner n tune up n the bottle and it stoppd a lot of the hard jacking it still does it but not real bad. I'm goin to also get sum plugs n wires foe the tune up. I'm at work but I have my warranty at home when I get there I'm goin to post some thngs an see wat u think. Thanks again Dan