I have a 05 350z De that i have been building ,one thing i have been fighting is the p1136 code , p0021 , and on off p0327 , the car has 151k miles , the codes are on when you get on it , if you start it baby it stay under 3500 rpm no codes. car runs fine and strong unless you get it to pop a code then it will sound like its missing surging

Ive done the normal , changed the VVT , changed the gaskets , pop checked the one i took off it was fine , changed the knock sensor and harness , harness in the car has been swaped out , old one was bad , ecm has been uprev tuned , changed the cam crank sensor with hitachi sensors , changed coil packs , plugs , injectors have been cleaned on tested , oil is new , fuel is new 93 . im starting to think the only thing left is gallery gaskets and timing.

complete parts from z1 are about $850 . im a diesel mechanic so i can spin a wrench , never messed with car timing but eh tomato tamato
JDM engine 2k

cylinders have over 200 on compression test so it is strong , i just dont know in the end is it worth it to fix or swap.