The knock sensor on a 1998 Isuzu Rodeo with the 3.2L engine is located
on the engine block, near the distributor. It's often near the front of the engine, but the exact position can vary slightly. You'll likely need to consult a repair manual specific to your year and model Isuzu Rodeo to get a precise visual location. A diagram in the manual will be the most helpful.
Because its location is somewhat variable and obscured, it's best to use a repair manual or online diagrams specific to your vehicle's year and engine. Searching online for "1998 Isuzu Rodeo 3.2L engine diagram" should yield helpful results.
