O2 sensor issue

I recent purchased my 92 pickup with a 22RE in it. Ran good for about a month and then has a surging idle and stumbling issue. After checking all vacuum lines, cleaning the throttle body, cleaning upper intake manifold, testing the TPS and setting it back to specs, and checking all injectors with a stethoscope, i still had the problem.

At this point, I purchased a new Idle Air Control valve (IACV), put it on and it ran good. Then I checked my ignition timing with a timing light and it was at 1 degree. 😳. Got it to approximately 5.5 degrees and BOOM it ran great….. for about 3 hours.

Now it started stumbling after it got up to temp and would completely die even at idle. Got a lot of black smoke and a gasoline smell from the tail pipe. Did some reading and everything pointed to a bad O2 sensor. The truck later confirmed my O2 suspicion when it there the code for the O2 sensor.

I crawl under the truck to make sure it’s not a loose/bad connection and there is NO O2 sensor anywhere. And I mean anywhere!

checked in with the previous owner who said when he replaced the exhaust system, he didn’t feel it was necessary to put the catalytic converter or weld bings on in order to put the O2 sensors back on…….

so I’m wondering, how did he drive it for 5 years with no issues from no O2 sensor, and why would it be biting me in the rear after replacing the IACV? And I’m trying to dig out where exactly I need to weld on a hung for a new O2 sensor and if I need to weld a cat back on it for propped operation.

also it is worth noting that the engine is set up for California emissions and here in Ky we do not have emissions testing.