I found this at AutoWeek:

Ford has temporarily stopped production of the 2003 SVT Cobra due to quality concerns.

Ford officials are mum on what’s wrong with the supercharged Mustangs, but assembly plant sources told media that the problem originates with the 4.6-liter V8.

Ford aims to resume production Nov. 15 and will begin delivering finished Cobras that were held back because of the snafu.

Ford temporarily stops production of Cobra due to engine problems