I'm not aware of any mod for it but there is a bug in GTA4 that requires you to limit the framerate to ~30 fps during one of the missions or you can't pass it. You have to button mash at one point and it's tied to keyframes that were designed around console performance.Seriously? I honestly don't know what you are talking about because I finished GTA 4 without needing any mod, and have never read of any such complaints from anyone else.
With that said I also experienced bugs in ME:A even after all of the patches, the one I remember running into multiple times was getting stuck in the terrain due to clipping issues.