And I think my oxygen sensor is finally slowly going out.. for almost 2 months it's been fine.. but after I did a ECu reset after putting on a new muffler (magnaflow) it's sometimes stumbles from idle to about 2500.

 

I was looking at the voltages at idle it's back and forth but last time I check with my o-scope I can't remember how fast it was reacting.

 

Should I use a wrench or a socket for the oxygen sensor?

used an offset wrench to do mine - unplug the sesnor, feed the wire thru the wrench and break it loose. not sure how well a socket would work with the wires....

I was referring to the oxygen sensor socket

I would use the box end wrench if possible. if it can't reach, THEN use a o2 socket.

Use an oxygen sensor socket. They are like $15 bucks at the advance auto. I can't tell you how many people have borrowed mine.

I just cut off the wires going to the 02 sensor at the sensor, then use a spark plug size socket on a 3/8" drive. Then I slide about a 2 foot bar over the end of the drive handle for added turning leverage. Install new sensor with an open end wrench.

If you can't get an 02 socket in there, a crowfoot wrench works well too.