Isuzu 1999 RODEO Workshop Manual page 954

Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
4. When the engine is idling or at steady cruise, the
HO2S voltage should vary from between
approximately 100 mV to 900 mV. During "power
enrichment" mode, more fuel is needed and the
HO2S voltage should rise above 447 mV. This step
checks to see if the HO2S is operating properly.
5. Wrap a shop towel around the fuel pressure
connector to absorb any small amount of fuel
leakage that may occur when installing the gauge.
Ignition ON, pump pressure should be 235–320
kPa.
7. Add Caution: Use correct pliers so damage to fuel
lines will not occur.
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION 6E1–327