I have a 2004 Nissan 350z and have been having issues with the power delivery. Under heavy throttle the car will lurch or bog at lower rpms, around 4k rpms it will be consistent all the way to redline. if I downshift and am around 4k rpm it runs smooth if I WOT. the car has some issues as it sits right now and I plan on doing them but I'm curious about what would be the best to do first. I have 3 consistent codes p1283 (AF sensor Bank 2 Sensor 1) and p0444 ( purge volume control valve) and a p0037 (heated o2 sensor) ill be replacing that this week. when I run errands and turn the car on and off a lot it will slowly get worse and worse and sometimes it wont even start and I'm stranded for 10 minutes just waiting till it will let me, when that would happen and I drove away it would pop a p0300 code (multiple misfires) and flash the CEL but if I continue to drive it clears out and runs like it has been again. and I use to get codes p0174 (fuel system lean B2) but I haven't seen that one in a while, possibly because of parts I've put in but unsure. but if I clear the codes and don't exceed 4k rpms I don't think these codes pop its mostly when I'm full throttle and near redline. But sometimes the car will start up great and run great as well so I don't know if its a computer issue, including the o2 sensors for the exhaust leak, or a fuel issues. I had the car dropped off at a shop while I was on vacation and they tested the fuel pressure and said it was good, but unsure of where they tested the fuel pressure as it has stock fuel regulators with no test ports. but they recommended i change the crank sensor so i replaced cam and crank sensors and it started to idle a little better but still same issues as before. I have also gone around the intake system with brake clean to see if I had a leak but didn't notice any change in rev when spraying. Also when downshifting if I let the rpms drop below 2.5k rpms and I try to gas it to match the rpm it will sometimes pop out the back and it sounds very very lean. It also has awful power delivery under 3k rpms, it lurches very hard and very slow to gain rpm if I start below 3k rpm, but to be honest I'm not sure where the power is best for this thing, but anywhere above 4k rpm is prime for acceleration anything below that is a prayer.

350z issues:
- think there is an exhaust leak but unsure where, the sound of the car on decel is very raspy but I'm not sure if its my exhaust or not. it does not sound like your typical z. possibly coming from the header which is before the O2 sensor so this is probably top priority to change.
- hard start, doesn't always crank on first key, sometimes it will, but most of the time if it does start first try its very slow to gain the rpms but will level out to normal after a few seconds.
- issue with the clutch as well, the clutch pedal constantly sticks if pressed for too long and I've replaced the master cylinder and slave cylinder for it. fluid is a little dirty but I plan on flushing it this week. the clutch also doesn't like to grab very well in 1st gear, I cant race from a dig because it takes too long to catch and I have to hold the clutch otherwise it drops out and lurches hard from that. but in a roll or any other gear after being in first at a stop, it runs fine and grabs well. but I think I need a new clutch for sure but I don't think it could pop the codes I have.
-the more you turn the car on and off it starts worse and worse
-car surges when filled up after its been running, usually wont surge if I hit a gas station first thing driving it. unsure if the fuel filler neck has been replaced or not, I've heard that can cause the issue but could it cause worse?

what has been done:
- replaced cam and crank sensors as recommended by the shop, increased idle speed from 550 to 750
- new slave cylinder and master cylinder for clutch, still sticking and I'm pretty sure the pedal is adjusted correctly
- has new Air/Fuel O2 sensors on both sides, still throws a code for bank 2
- New MAF sensor , no change in that
- new purge volume control valve ( on motor) and purge valve (on Evap box)

I'm just trying to see if you guys have any other ideas that I haven't thought about, My main priority I think is to find that leak in the exhaust and then replace the clutch soon, but if its possibly the fuel regulator or something someone else has experienced before id love to know all possibilities. I've even thought that the evap box could be a culprit since I keep getting the purge volume control code.