Very rough idle, PO161 code
Well it's been a while since I've broken my truck, so it's good to see you all again.
About two weeks ago my truck started idling really rough. The RPMs drop to 500 then surge up to around 1100, then start over again. My truck has 130k on it and the oxygen sensors have never been replaced so I thought that was most likely the problem. Replaced the two primary sensors and the truck still idles horribly. I've been told all sorts of things: PCV, TPS, O2 sensors, bad cats, IAC, etc...
So I scanned the codes and came up with a PO161, which is some sort of malfunction in the downstream driver O2 sensor. While doing some inspecting around there, I noticed that the wires on the downstream passenger O2 sensor have worn through and are possibly grounding on the tranny mount. That one obviously needs to be relaced.
So I want to know if I can expect the truck to run fine after replacing the back O2 sensors. If not, what should be the next step I take?