Oxygen Sensor
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
See ENGINE SENSORS & SWITCHES .
NOTE:
If injectors are dirty, they should be cleaned using approved injector cleaning procedure before performing port fuel INJECTOR BALANCE TEST.