I play xbox live a lot but this past week I have been lagging a lot. Will changing my ip stop the lag?( just in case your wondering there is no bad weather and nobody is on the internet when I lag)

Lag is caused by the congestion in the network (or internet) between you and the xbox live server, or you and the people you are playing against. If you changed you IP, you would still have the same physical connection, and most of the time, be routed through the same networks. A new IP probably wouldn't help at all.