I'm getting 0.05 volts at warm idle. If I go to 3000 RPM, it goes up slightly to0.06 Volts. As I deaccelerate it briefly goes up to 0.7 to 0.8, then back down to 0.05 at idle.
What's going on?

 

So from what I have gathered from other posts, my downstream O2 sensor is showing high oxygen. Thus, it is not being burned by the catalytic converter. the sensor is about a year old. The only code I'm getting is cylinder 4 misfire. I pulled the spark plug and it look fine but the gap was 0.06, so I change it to 0.042. So, do I need a new cat?

 

The O2 sensor is showing high oxygen because of the misfire, that cylinder isn't burning the oxygen during combustion.
That O2 sensor is doing it's job sensing oxygen in the exhaust, A bad cat would be a P0420

You need to figure out the misfire first.

 

Makes sense! I'll work on that. Thank you!