In to deep.. 04 350z Enthusiast 04 350z touring I'm just winging it rn
 

Own 2 350z both are 04 coup.. the one that's running weird has 157k, on the dash. I got it a week r 2 ago and I think I might have got a good deal for it just runs funny has no engine light on but stutters at idle, after a decent drive.. then fist day driving 45 mis to work i left home and all lights gauges where looking normal i checked oil psi few mins later and its pegged 120 and needle moves a little bit but hasn't read below 100 sice. Idk if I should be scared or not I changed oil and looks normal put now filter from what I was told there hasn't been 'any BIG failures while they owned it idk how true that is..... regardless its my problwm now n i have no clue what direction to start with trying to do a complete overhaul and tune up myself never done maintenance on my first 350z, so what are specific things that i need to check or replace for a beat amd abused 04

Thanks for any help or advice given
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Change the oil pressure sender. If it's still high. the bypass could be stuck closed.

will doo