The crank sensor on a 1999 Oldsmobile Intrigue 3.5L Twin Cam V6 is located at the
rear of the engine, on the transmission bellhousing. It's often near where the transmission bolts to the engine block. You'll likely need to get underneath the car to see it clearly. It's a relatively small sensor, often with a single wire connector.
Important Note: Due to variations in specific models and potential aftermarket modifications, this is a general location. Always consult a repair manual specific to your vehicle's year and model for the precise location and removal instructions. A visual inspection aided by a repair manual's diagrams is highly recommended.