The “Check Engine” light came on in my old car this weekend. On Sunday, I used a code reader to determine that the oxygen sensor heater was bad.
So I went down to the parts store and got a “universal” replacement O2 sensor. The cable was not cut to length, nor did it come with a new connector. I had to cut the cable, then attach the old connector using a very complicated splicing gadget provided with the new sensor. Getting the old sensor out was a bear - took a slotted, deep socket and at least half an hour of wrenching, tapping, spraying with penetrating oil, repeating. But it finally came out.
The new sensor, complete with cable that I literally had to manufacture myself, right there on my front porch, went in easily, but the tool wouldn’t fit around the new connector. So I could only get it hand-tight.
Reset the trouble code, started the car…no “Check Engine” light. Made it to work this morning with no light. F yeah! Yay for me!
Excellent. Enjoy your improved performance and acceptable gas mileage. Change your oil. Nissan guy told me when mine went out that I was pouring so much fuel into the cylinders that a lot of it was getting by the rings and contaminating my oil. He didn’t change it, nor did he offer to so I was inclined to believe him. Should change it anyway.
Next time, try warming your car up so that the exhaust pipe is juuuuuuust cool enough to work with so that you don’t hurt yourself. This is supposed to expand the threads on the o2 sensor which makes it easier to remove without damaging the threads on the pipe & part. I bought a generic sensor once. I pay more for the one with the right wires now whenever I can. You know why that would be.
Hooray for another shade tree mechanic! Ready for that timing belt now?
Yay! Send yerself a bill for $750!
(Next time add a little copper anti-sieze, for the next poor owner that needs to replace the sensor. That may be you, it may be someone else, but a little good Carma goes a long way.)
Ditto. Those little Carmas will go forever but you gotta be diligent about oil changes and routine maintenance. 
karma
uh oh…did I get whooshed with Carma? :smack:
Well, it was hard to see, but the keyboard monitor saw it as K<backspace>Carma.
Can you tell me how to go about doing this on a Lexus es300? Mine is broken and I don’t want to spend $1500 to fix it either. Also, what do oxygen sensors do?
I was just about to do the same thing with my car. My check engine light came on and the onboard computer said it was an emissions problem caused by bad O2 sensor. Trouble is, I’ve got two in my car, one before, one after the catalytic converter. One was about $100, the other about $60. I wasn’t sure which one was bad and I needed to get new pulgs, get the brake fluid and coolant flushed anyway. Decided to take it to the dealer to do the work.
Turns out, it was the MAF (mass air flow) sensor. Covered under warranty it was. Along with some minor recall fixes and of course the usual inspection. Clean bill of health.
I’d have been pissed off if I’d replaced the O2 sensor for no reason and still had a problem. :smack:
But good on you mate! 
Ask and ye shall receive.
They sense oxygen. In the exhaust. When they cease to do so, your engine don’t run right.
Normally if you can change a spark plug, you can change an OS. They’re about as big as…well… a spark plug. They live on the exhaust pipe somewhere between the motor and the cat converter. Get under the car and have a look–you’re looking for what appears to be a bolt with a wire coming out of it. There may be or two for inline engines, 1-4 for a V-6 or V-8. I usually get mine off with a regular old wrench.
Easy to replace in concept, just swap 'em out & reattach the wire. Some require a 4 foot arm with three elbows, however. I did an Isuzu Trooper that required me to remove the front drive shaft just to access the thing. Took an hor to get to it, 5 minutes toreplace, an hour to put the shaft back on. bleah.
Good gravy what an awful post…