3. Check For Exhaust Gas Leak

1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (Manifold).

Fig 1: Checking For Exhaust System Leaks

Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG 

1. OK: GO TO 4.
2. NG: Repair or replace.