Where is the oil sending unit on a 1998 Toyota Camry 4-cylinder?

The oil pressure sending unit on a 1998 Toyota Camry 4-cylinder is located on the lower part of the engine block, typically near the oil filter. It's a small, usually one-wire, sensor. However, the exact location can vary slightly depending on the specific engine (e.g., 2.2L or 1.8L) and might be somewhat obscured by other components.

To be absolutely sure, you'll need to consult a repair manual specific to your 1998 Camry's engine. A picture in a repair manual will be invaluable. You can usually find these manuals online (often in PDF form) through sites like Haynes or Chilton. Searching online for "[Your Camry's engine code] oil pressure sending unit location" might also yield helpful images.