Lazy o2 sensors?

[mustang_52]

I got a rough idle so I'm trying to figure out whats going on. There is no mil light or dtc's. Im using a genisys to read some of the parameters. As the car begins to warm up, i notice b1s1 reads zero for a minute before it starts to climb and b2s1 climbs normal from the start. Once closed loop is obtained, both b1s1 and b2s1 flucuate like normal but b1s2 and b2s2 stay pretty much around .800mv. Does this sound normal?

[02z28ls1]

Yes-the rear sensors do not flucuate much once the cats have warmed up.It indicates that the front ones and the cats are doing their job.If the front O2s are flucuating that indicates proper operation and it would set a code otherwise.

[Bombguy99Z28]

rear o2s have absolutely no effect or input to how the car drives, purely an emmissions thing to verify the cats function. Your front o2s should oscilate in a sine wave while in closed loop (normal, warmed up part throttle driving) and stay steady around .900ish in open loop.