Where are the spark plugs located on a 1999 Chevrolet tracker 16L?

The spark plugs on a 1999 Chevrolet Tracker 1.6L are located on the top of the engine, under a plastic cover. To access them, you'll need to remove this cover. They're arranged in a line across the top of the engine, one for each cylinder. You'll need a spark plug socket and wrench to remove them. A shop manual specific to your vehicle year and engine will provide more precise details and diagrams.