The horsepower of a 1999 Ford Mustang varied significantly depending on the engine option. There wasn't a single horsepower figure. You'll need to specify the engine to get an accurate answer. The common engine options included:
* 3.8L V6: This typically produced around 190-200 horsepower.
* 4.6L V8 (GT): This generally had around 260 horsepower.
So, you need to tell me which engine was in the 1999 Mustang you're interested in.
