I replaced one of my o2 sensors on my 95 z28. I also purchased a new connector and spliced it in. Now, when the car warms up it stumbles like crazy with ANY load on it at all. When I turn the car off for a minute and turn it on it runs okay, but only for a short time, then it's back to the terrible stumbling. Both o2 sensors were original, and for quite a while the car was running very rich, so the other is very possibly bad. Now my question is, does the fact that one is new now, and one is still bad mean that's probably the problem? I know you are going to ask why I didn't just replace both, well as much as I hate to admit it, I didn't know the other one was there And I haven't bothered to just get a new one because the weather here in Michigan isn't exactly supportive of our passion for dry asphault and sunny days.

 

Id change the other O2 and also make sure your connection of you splice is a good one. Solder it if possible.