Muffler (passes exhaust) & Knock Sensor/Oxygen Sensor codes j30t

[610]

Hello everybody!

I've just bought infiniti j30t 97, I like it, great car, but it has several issues.

Muffler is leaking exhaust near place where oxygen sensor is situated, but it can be weld. - Can oxygen sensor code appears because of leaking exhaust?

Also I think last owner put regular gas into it. Can knock sensor code appears because of mixed octane rating once, and then it should be just flushed after I will put premium gas?

Also the engine is pretty clean. Can they brake connectors for knock/oxygen sensors while they were washing it?

Thanks in advance for answers! I'm newbie in this, so don't be mad on me for stupid questions, please :-[
Modified by 610 at 3:54 PM 1/27/2010

[610]

I've just found a posthttp://forums.nicoclub.com/zer...95043it looks like i have the same