Hello,
I have an AutoXray scanner and it shows that my O2 sensor jumps all over the place (.2-.8) when at constant speeds just driving around. At full throttle it stays at about .85 and doesn't move. The car is a 88 Iroc 350 tpi with 150,000 miles on it. Is this fluctuation the sign of a bad sensor?
thanks

 

It needs to fluctuate. Wider the ban the better. On my scanner I get .090-.920 When underload and WOT its going to need more gas which is why the readings will stay in the .700-> until you let off the gas.

 

Mine does the same thing. I am not sure about the WOT, I have not checked mine yet. I am curious to find out what the O2 should be reading.

However, I am getting the same readings with a 87 carb setup, using the LG4 computer. I am surprised TPI and Carb are that similar. I would somewhat expect reading to be jumping around on a carb, but not so much on TPI.

Oh well,
Bill

 

WOT the o2 senor should read about .850mv to1.000mv, lower than that, you are running lean..in wot.