The model code for the Porsche 911 produced from 1999 to 2004 is 996.
The Porsche 996 is the fifth generation of the 911. Its production began in 1997, with the main generation running through 2004; the question’s 1999–2004 period captures much of its commonly cited production era. Porsche replaced it with the 997 in 2004, although certain high-performance variants continued longer.
The 996 represented a major technical break from earlier 911 generations. It introduced a new chassis platform and Porsche’s first water-cooled flat-six engine for the mainstream 911, replacing the traditional air-cooled arrangement. The standard Carrera initially used a 3.4-litre engine and later switched to a 3.6-litre unit.
The 996 is also commonly recognized by its “fried-egg” headlamp design, shared in modified form with the 986 Boxster. Enthusiasts sometimes confuse its code with 991, 992, or 997, but those identify later generations: 997 followed the 996, while 991 and 992 came afterward.