Well, I bought a 350z 2 years ago. Never owned a Z, and I had a Honda before.
I drove 2 years absolutely ripping it. Had a ton of fun. Car sat for a few months and when I came back to it, I was much more developed in mechanics.
This was the first time I noticed the SES on, even though I have a video of the dash when I bought the car and it was on then.
I had noticed bad high end acceleration and some pretty nasty low rpm bucking in the time of owning it, but my friend said it was because I crap at driving stick. I doubted him and took the car to 2 different local mechanics. They both said nothing seemed wrong with it. So I ignored it and rode the clutch a bit more (hey if you just bought a car and people that know more than you are saying it's fine you'd keep driving it too).
Well I finally scanned for codes after 2 years.
Only one code.

P0327 Code

So I opened her up exposing her beauty to my eyes. Replaced the harness and sensor, reset the ecu and the code is gone. but I've noticed it smoking a bit more than usual.
How likely is it that I've mangled my engine. Could that sensor really cause engine death in these cars? How safe is "safe mode".
I'm kind of panicking because I love this car but lack the money, knowledge and time to replace pistons, rings, seals.
The motor has 130k miles on it. What do you guys think? Tell it to me straight people.

Thanks guys