To find the precise location:
1. Identify your engine: Check your vehicle's paperwork or the sticker inside the driver's side doorjamb. This will tell you the engine size (e.g., 2.4L, 3.1L, 3.4L).
2. Consult a repair manual or online diagrams: Once you know the engine, search online for "2001 Chevrolet Malibu [engine size] O2 sensor location" or find a repair manual specific to your year and engine. A repair manual will have diagrams showing the exact placement. Websites like Haynes or Chilton often have these manuals available for purchase.
3. Look under the car: With the engine off and cool, carefully look underneath your car near the exhaust manifold (upstream sensor) and further down the exhaust system (downstream sensor). They are usually threaded into the exhaust pipe. They are typically cylindrical with a wire harness leading to them.
Caution: Working under a car can be dangerous. Always use jack stands and never rely solely on a jack. Exhaust systems get very hot, so allow ample time for them to cool before working near them. If you're not comfortable doing this yourself, take your car to a qualified mechanic.
