To be certain, you should:
* Consult your vehicle's repair manual: This is the most reliable source for the precise location.
* Use a repair database: Online resources like AllDataDIY or Mitchell 1 (subscription required) often have diagrams showing the sensor's location.
* Search online for images: Searching "1998 Pontiac Grand Prix crankshaft position sensor location [engine size]" might yield helpful pictures.
Remember that working on your car's engine can be dangerous. If you're not comfortable with automotive repair, it's best to take your vehicle to a qualified mechanic.