Where are the 4 oxygen sensors located on a 1999 Isuzu Amigo?

On a 1999 Isuzu Amigo, the four oxygen sensors are located in the following positions: one upstream (pre-catalytic converter) on each bank of the engine, typically positioned in the exhaust manifold or just after it; and one downstream (post-catalytic converter) on each bank, located after the catalytic converter in the exhaust system. The exact locations may vary slightly depending on the engine configuration.