I bought 2 oxygen sensors for my 1991 LX, 5.0 convertible. I removed the old sensor on the driver's side and put the new one in, which took about 3 minutes.
The passenger side sensor is another story. I have tried for 2 days to remove it, with no success!! I have the special socket and I'm getting a good grip on the old one, it just won't budge. I have used PB Blaster lubricant on it, hit it with a hammer, still nothing.
Anybody have any tricks up their sleeve?
I have to replace it because the old one's wires are torn up.
What will happen if I drive the car with one new oxygen sensor and the other one
Hit the bung with a propane torch and get it nice and hot. Spray it with some type of penetrating oil while it's hot, and it will draw the cool oil into the threads. Yes, it will smoke to high hell and smell like a barbecue grill, but it works. It'll still take some effort to remove, but it'll be a lot easier than just fighting with it using the socket and oil.
You might be able to get away without a torch if you try it while the exhaust it hot from driving. I picked up a propane torch for like $10 from the local Ace Hardware in town by me. One word of caution though, your entire exhaust system is going to be damn hot if you do it after driving, versus just the one area when using the torch.