So I got a car from this guy turned out a car was fraud from the original post and it was already too late he didn't want to give me my money back so I have his car it's got an engine light on I take it to get a tune-up the engine lights go off I got new tire change and neutral safety switch Tightened twas loose. On the way home the knock sensor code goes on. I had a somewhat shady mechanic take a look at it we replaced the knock sensor and then it went back on and the mechanic said all that it was fine and that it's probably just you know it's a 24 year old car.
Anyways he did a janky job on an oil change and I took my car to somewhere else and they replaced the knock sensor again here's his notes"

Note: Vehicle has several codes

P1259 VTEC system failure

P0325 knock sensor no signal

P0302 misfire cylinder 2

P0304 misfire cylinder 4

Since engine is not misfiring right now and VTEC system seems to be working properly I'll just focus on knock sensor code.

I checked for 20-30mv coming out of PCM for that knock sensor and I'm getting 27.1mv which is within specs, next checked for the same voltage at the actual sensor connector and I'm still getting 27.1mv which is perfect, I then made sure that wire was not grounded and it's not so after I did a load test on that same wire to make sure its completely intact and it passed load test telling me the wire is okay. At this time connector, wire and PCM seem to be okay which only leaves the sensor itself to be bad so I'd rec replacing it even though it's new it's very possible that it's defective.

Side note - When I pulled out PCM and unplugged the connector for that knock sensor wire to test it there was oil inside the connector and all over the PCM pins which could cause major issues in the future, I did clean it up but would definitely let customer know he could have further issues if that continues to happen.

"" Diagnose Oil Leak to Computer

$166.50

After doing some research I found that if oil pressure sensor or VTEC pressure sensor are leaking a lot then that could cause oil to slip through the wire and make it's way to the other end. I had to make sure at least one of these sensor wires were connected to the PCM and in this case the VTEC oil pressure sensor is connected to that same connector where we found the oil in the PCM and this sensor is leaking a lot of oil so for now I'd rec replacing that VTEC sensor cleaning the PCM and that should take care of it.

End of mechanic notes.

I just picked my car up from their shop yesterday and today I was driving in the morning and my check engine light came back on sob so I resorted to my lucky handheld reader code reader and I've got p0325 again!
And a p0420 code. And a separate code for p0420 that says pending .