Opinion needed

So I have been trying to smog my jeep in ca. Recent work on my 91 4.0 is new banks header, new o2 sensor, new plugs,wires,cap& rotor. So my question is I also sea foamed the motor via the brake booster vacume line. I have done this twice. The first time it smoked bad, the second time wasn't as bad but still a lot of smoke. Before I replace the cat should I finish the can of sea foam and see if anymore smoke comes out or is twice enough? I have failed nox twice btw. Trying to head it off before its a problem AGAIN!

Try some down the throttle body to

Oxides of Nitrogen form with high combustion temperatures-- as yours is a '91 (no EGR valve) you should look into causes of high exhaust temps. The most likely cause is a lean mixture, but advanced timing can contribute as well.

I would run a fuel pressure test and verify sufficient pressure and a fuel volume test to verify enough fuel is available. Assuming it passes those tests, start looking for vacuum leaks.

My numbers were good across the board untill It got to NOX. My NOX numbers were three times what they had to be to pass. When I replaced my cat I drove it for a week and took it back and my NOX was in the single digits. Check every sensor on your engine with a multimeter to make sure it is working properly and if they are then you probably need a new cat. You should also use a lambda calculator to see if you are running lean, if you google lambda calculator you will find one you can use.

Also, when I sea foam my motor I use half a can each time, so I would either use the rest of that can through the brake booster before you get a new cat or throw it in the gas tank.

Lambda results were perfect on both 15&25 mph tests. 1.009 on 15mph, and 1.004 on 25mph. Only sensor I know isn't working is the t-stat. I read here not long ago that it could affect operation, but I'm not sure how much. Someone said they just unpluged it and passed. I might just go pull an old one from pick n pull I don't really even look at it often, and know it runs about 185* with my 3 row radiator. Idk I guess I will just finish that can of sea foam install new cat and then retest.