Note On Intermittents
With engine running, manipulate O2 sensor harness, PCM wiring, and connectors while observing PCM parameter ED33. If fault is induced, ED33 will jump to greater than .63 volt and ECON status light will go on. Manipulate circuit No. 413 ground to engine, and look for a loose ground eyelet or ground eyelet installed at wrong location. If O2 sensor circuit is okay or lean engine operation is suspected, perform PFI SELF-DIAGNOSTIC SYSTEM CHECK . If O2 sensor circuit appears to be okay, go to PFI CHART A-6, OXYGEN (O2) SENSOR TEST .