Re: Oxygen Sensors and Their Role in Engine Management--A Primer
That's true but, if yours are indeed lazy, biased or outright bad, the downstream sensors are probably in about the same condition as the fronts. For the additional $60 or so I'd change them too. This is especially true if you don't have any way to monitor the real time voltages of the various sensors and the cat. temps.
I just got back from an 800 mile trip and spent a little time monitoring my 02's. I may have a slight exhaust leak on the right side, as my 2/2 reading would periodically drop below .450 mV and then go back to normal operation after a short while. When it did this, the 1/2 sensor crosscounts would slow down, tending to spend more time on the rich side. I guess what I am saying is that if the rears are malfunctioning, but not mirroring the fronts, the PCM still takes action to correct the mixture....in my case (potential exhaust leak) add more fuel. As a side note, my fuel economy was down a little more than it should be for this time of year, and the type of driving I was doing.
05 LX/RT and 06 WK/GCO, (modded similarly) with MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tubular headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 85mm TB, SOS Coils/.060 spark plug gap.