Just bought Gangstar: West Coast Hustle on my iPhone 4 a few days ago and once i started the first mission, which is stealing the car, i drove my stolen car and after a few seconds, it lagged. it continues lagging every two seconds or so and when my car crashes with another vehicle, it will lag seriously. I've already tried reinstalling it but to no avail. Furthermore, I've tried to reinstall the application and restart my device but it doesn't work. I've also tried restoring my iPhone and realised that my phone was not the problem as other applications on my phone worked pretty smoothly. Any solutions??