ok guys, my '93 Z28 has been acting up lately. sometimes it'll run perfectly smooth, and others it'll start missing like a blind guy firing a machine gun in the dark. i checked my O2 sensors (and replaced the drivers side sensor, cracked housing), but now both sensors are reading horribly wrong.

drivers bank has been showing 0mV, passengers side between 600-700mV. they are both reading either pig rich or stupidly lean (it's at the shop right now, and my mechanic is all but stumped with it) and being slow to switch. ECM is reading the same thing as the scanner is too.

anybody have any ideas???

 

I would say take the o2 sensor out that is reading 0 and bench test it. If you wave a torch over the sensor it should generate some type of voltage.

Did you get one of the universal replacments or an exact fit? I prefer exact fit even if they cost a little more than the universals do. Also I have had really good luck with Bosch sensors, not so much with the other brands.

Massey

 

it was an exact fit Bosch that was replaced.

 

from what i have read and seen, lt1 does not like bosch 02 sensors. sometimes they are ok. mine did not like em. make sure theres no exhaust leaks and the exhaust is grounding. also check the 02 wires for damage and/or shorting to ground.