ps2 problem

[mike_gt2]

i have a V5 ps2 with an autokey modchip. @ 1st it worked great but now when i play my games like NFL 2K3(original) and its not scratched or dirty, it freezes when ur by the midlle or the end. the same happens to the backups @ a more random time. also another thing inoticed is that for example when im playing nfl 2k3, i hear a tick tick tick sound and then the game gets choppy then freezes, this happens on the backups too. all my backups used to work perfect. any suggestions.