Can splicing in wire to extend the length of the o2 wire since it's too short for the coupling to connect cause false readings? Someone mentioned it today, and ever since I installed the headers I've been splicing in wire because my o2 bung is farther back so they don't reach. I can't imagine it doing that, but I'm just too tired and stupid today from lack of sleep last night.

put the new (expensive this time) o2 in last night and already got a code 13 this morning. It was in closed loop for the most part today I think.

 

If you moved the o2 sensor from its original location (ie. farther away) it may not be getting hot enough. You may have to go to a heated three wire sensor that has its own heater and does not rely on exhaust heat to warm up. 95 chevy trucks with a 350 had these sensors.

 

Some of the original and older style sensors used a hollow wire to supply the reference air to the zirconia signal junction. I believe that most newer and replacement sensors vent reference air through an orifice in the sensor body, but there may be some which use a vented lead.