Car turns over but won't start
 

Hey guys. I need help! Got a 99 SE. My last codes were P0141 (Heated O2 sensor, Bank 1 sensor 2) and the knock sensor. I've seen in the forums that the knock sensor can sometimes be a ghost code that will go away after you fix the O2 sensor. My car (I just realized) is California emissions. So I switched out the O2 sensor and now the car won't start. The starter seems to be working (just replaced last year) but it just won't start. It was showing signs of starting troubles before I switched out the sensor. (Didn't seem like it was going to 'catch'. Idling would drop to 200rpm of so before picking back up to 750).

I will make a couple of notes here. First, I had switched out this exact sensor two years ago, but being stupid never even bothered checking if the car was California emissions (I live on the East coast and bought the car 1 year old in NC). So the O2 sensor was NOT Cali. I also replaced bank 1 sensor 1 at the same time - also not Cali. The car ran fine. Got about 22 mpg.
So I'm trying to figure out why the heck the car won't start. Is it possible that one of the wires snapped on the wiring harness on the other side of the O2 sensor? I have not checked continuity yet on that. (Was too frustrated).

Any ideas? I will also note that I am only slightly above a novice mechanic.

I just read slowyota's post and it seems that a few of those issues could be what I'm facing. I will say that I have zero codes after the O2 switch-out. That's what's frustrating. Computer probably needs you to drive it to realize there's a problem!

not always it can tell if its not getting any reading from a sensor

and a bad/unplugged o2 will not keep the car from starting

if you read slow yotas post... one person on the last page mentions something about the security ..,. does your red light stay on?

other then that add a ground and test sensors

Just checked. Security light goes out. I have been having electrical issues the last 6 months. Dome light burned out 1 week after I replaced it. Just had the alternator replaced b/c it was not charging the battery at all. When that was done, the 7.5A fuse that's connected to the clock snapped. Just weird stuff. I'm thinking the ground may be worth a try.