Last post on Jul 12, 2011 at 6:24 AM
You are in the Pontiac Grand Am
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Pontiac Grand Am, Electrical, Engine, Fuel Efficiency (MPG), Fuel System, Sedan
#1 of 2 1995 Running rich - odd 02 Voltage reading?
Jul 11, 2011 (9:58 am)
I've got a 1995 Grand Am with 3.1 motor. It has been running rich, and I've replaced just about everything except the PCM (computer). It gets horrible gas mileage and leaves black soot around the back side of the car.
While probing the O2 sensor input to the PCM, I noticed that the voltage seems to turn on and off... It will go from about 0.6V to 0.0V and back every second or two. I always assumed that this would be a more-or-less constant voltage with small fluctuations as the mixture is altererd.
Anyone have any experience with this that could lend some advice?