Have GT4 on a Playstation 2. Worked flawlessly for a couple years with the original and aftermarket controllers. Now, for some reason, the throttle position indicator shows that I am not getting full throttle consistently (and the lap times are slower too). Sometimes the throttle works fine, other times it only allows between 60-80% throttle. Pretty frustrating! I thought it was a controller problem, so we purchased new controllers. But the problem persists with the new controllers as well. Any advice on what to try to fix the problem?