I purchased a set of NTK upstream o2 sensors to address an check engine code 25 and trac light. On a 90 LS400 64k miles.
Previously when I bought the car I had a small leak at the rear cat flanges to exhaust pipes. An exhaust only custom shop cut and replaced the bad metal. I reset the lights but they came back.

When I went to install the sensors I was unable to seat the replacement plug into the engine harness. I pulled them and saw the seperator difference. I can't see into the harness on the engine but it's the only thing that seems to make it so I can't seat the electrical part.

I called rock and they said ALL including Denso have the same (+) lifestyle connector and not the (-) like I pulled. I'll buy OEM if I have too But at 3x's the cost I don't wanna spend the money to have to splice harnesses.

anyone else ever have issue?