Mercury Villager O2 Sensor

villagridiot

I bought a 2001 Mercury Villager about a year ago. Nissan 6 cyl engine 58K miles on it. Runs smoothly, but never got good gas mileage. 11.5 to a little under 12 MPG. Recently the CEL has been on steady. I had it checked at a auto parts store and am getting a Code PO141 and Code PO325. I understand the 325 is the knock sensor and, upon reading further, that i would be better off bearing the pain of chewing aluminum foil than changing this part. The knock sensor seems to indicate other problems. one of which is the PO141 code. However, I did not see anyone else with this code problem. this is the oxygen sensor. My question(s) are: is this a hard part to replace? where is it located? Would I better served to replace other parts instead of, or as well as, plugs, rotor, distributor cap, etc? I get suspicious of some of these codes masquerading as other troubles. incidentally I have 64K miles on it now.

stever

Rule #1 is don't change the knock sensor on these vans, at least not until you rule everything else out. I'd check the wiring before replacing the sensor, especially if it's the rear O2 sensor that's supposedly at fault.