2008 Infiniti G37S Coupe 5AT

Mods: Catless, Aftermarket Intakes

My Infiniti has been stuck in limp mode ever since I got it a few months back. If I reset ecu, the car will go to 3.5k rpm then limp mode activates. If I don't, the engine light comes on and I can't go past 2.5k rpm.

I've been to 2 different Nissan/Infiniti specialist shops and they both told me I need a new engine. One shop said I needed to replace the timing chain, and the other said gallery gasket, but he opened the engine and said it was already replaced beforehand so he deemed the engine unfixable and said I need a new engine.

Has anyone had a similar issue to me with these codes and what did you do to fix it going into limp mode? I am saving up to swap the engine but should I get a third opinion? What should I do from here?