PS3 NFS The Run Online Problem

Hello, I got the standard greatest hits version of Need For Speed The Run, the game work great and all but when I try the online mode the problems starts, I sometimes got graphics errors, track or players getting stuck,  a black screen when loading the next race and also sudden disconnection.

I read online that you can try deleting the install data and downloading again, tried that and the online works fine for 6 races (2 session) but starting the 3rd session the graphics problems begins and then my console freezes and I have to shut it down.

I want to know if there is a fix for this.

Thanks in advice.