Question about Xbox 360 and lag on HDTV

[bls]

I have a plasma tv and everytime I play this live 09 online I'm experiencing an extreme amount of lag when controlling my players.

I have a 1080p. At first I had my xbox set to 1080i and I it was alittle worse because when I would be at the freethrow line when the meter moves to the right it would lag according to when I pushed the button. So I switched my 360 to 1080p and it fixed the freethrow lag but when I'm controlling my players there still a step behind of where I want them to move when I move them.

Any body have any ideas of what I may need to do. I have a rear projection that I use to play on before hand and never had these issues until I just bought this plasma.