Dam, o2 sensor won't go in all the way.
 

It won't go in all the way into the y-pipe, there's about 3-4 threads or so left. Is this something I need to be worried about? Am I going to get an exhaust leak, etc?

Ugh... ran the car for a while and got a cel... what do I do? Come on, it's christmas. Help out a fellow max owner?

what kind of pipe? I had a problem when I got my budget y-pipe.. When I screwed in my front o2, it got kind of stuck and I forced it, screwing up the threads on both the pipe and the o2 sensor. Upon later inspection, I found there was some sand in the threads of the pipe, they weren't quite clean. We were able to fix the threads on both pieces with a dremel and a screw driver.

I would remove the o2 sensor you think is the problem *carefully*.. inspect the threads on both parts.. if they look ok, spray down the o2 sensor with some brake cleaner to clean it.. get some antisieze and put it on the threads and try to put the o2 sensor back in.

http://hakker.org/maxima/mike-ypipe.jpg

Oh yeah, whatever you try, make sure you clear the codes so you know you are starting clean..

It's also a budget... man, I already crammed the thing with a lot of force. I hope the threads aren't too screwed up. Yeah, I'll try that tomorrow.

Clean the threads..
Goto a parts store, but a "threader" (little bolt that you screw in and it will re-thread your hole).. make sure its the same size as the o2 sensor..

Ugh, Dammit, I broke an o2 sensor. All after holiday expenses too. Is it harmful to run the car with a busted sensor? The wire got twisted around the o2 socket and got broken.

I drove around with a bad o2 sensor for a month before I got around to replacing it, no problems..