I have an oldie with an ECM problem, an 83 Pontiac STE 6000 with a carb'd 2.8 that has an ECM with no codes. The ECM will only come on with a warm engine and will turn off if I restart. I 've cleaned the ECM ground. The O2 sensor will have cross-counts and range from .3 to .
8V and then stick at .8V at idle. The voltage will drop to .3V if I rev the engine. The O2 sensor was replaced 5K miles/5yrs ago. No bad O2 codes. Do I have a bad O2 sensor. Other ideas?- posted
15 years ago