> Look, i know i don't have NFS:PS on my PC, but have you ever installed any mods replacing the mustang? Then you should check if you uninstalled the mod correctly. Or it could be the grill texture of the car are corrupted and the game used the default grill texture (this happens on many modded NFS games).
For your information , this also happens on the original game. NFS PS is known to have this issue on most of the cars. As AceOfSquares said , the grill texture is indeed badly mapped , and in order to fix it , you have the choice of fixing it ( which means extracting , editing then reconverting it ) or to modify the texture folder to add a bigger one.
At the moment , the first alternative if the easiest one.