Hey guys. I'm having a bit of an issue with my 350z. I bought it with a blown motor due to over heating. I have an 06 z with a MT and a REVup edition motor. Instead of rebuilding the engine, I swapped It with a REVup engine from an 06 G35(was tested and checked before hand and everything worked properly). Everything plugged in just fine. Except for The oil pressure sensor in the oil pan which I just replaced with the one in the original motor. The Z now has an issue where it chokes or stutters at 3.5k RPMS and then will finally rev up and keep doing it at 4K 5k 6k. I do have an engine code of P0340 but I have replaced that sensor 2 times and for some odd reason depending what sensor I put in i get different reactions. I changed it with the used and new and they all have a different affect on the car but none fix the issue. Original one makes it worst and stutters at all times but cranks right up. The new makes the car hesitate to start but revs up better but still chokes at he 3.5k rpm mark. At some point of driving the car for a while(as long as I'm easy on the throttle) it will rev up smoothly as if nothing was wrong but will still choke at about 5k-6k Rpm range but if I am heavy on the throttle it'll stutter after 3.5k rpm again.
I did have an oil leak which was fixed but issue didn't go away. I do have a leak in my Y pipe.. but I'm Not sure If this will affect since problem isn't constant.
Also, if gear is in neutral the choking NEVER HAPPENS if the car is in gear it will happen with out a doubt moving or not moving still happens.
This is the only constant factor other than the Rpms it chokes at.

Dude. I’m having the exact same problem! Did you ever find a solution?