I don't know why my thread keeps getting deleted, since another thread similar to this was allowed but WTF does this thing go to? I've checked my wiring diagrams and haven't found anything on it. Comes out of the same loom as both the pri and sec O2 sensors.

 

What body/Engine, Year? Evap purge?

 

my guess is a EGR plug.
assuming it could be a crx hf?

 

https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/what-connector-2480763/ there is your old thread. Yes its egr hf crx's were made for good gas milage and have egr's

 

Oh, well thanks for pointing that out, for some reason it wouldn't show up in my threads created section. It is a 90 HF, with a B16 swap. I'm currently throwing a Code 1, would this be related? I went out and drove the car for about 40 miles with no code, running decently, until I got this code. I know it's for an 02 sensor, but since the headgasket was just replaced, I figured it unlikely that the O2 sensor failed immediatly.

 

just a question but did you covert to obd1 if not are both your o2 sensors hooked up

 

Still obd0. Both O2 sensors are connected. I would have thought if they were getting a bad a connection it would throw a code longer before I drove it 40 miles.

 

Use a chipped p28 computer go obd0 to obd1 to the computer. Computer is more manageable and it can also be programmed to ignore alot of those unneeded sensors on that swap. Is your Vtec working properly. Does it cut off after driving a while but come back when restarted?