hello! I wouldn't be posting this if it wasn't my literal last resort but this car is about to make me go insane. I've owned the car for 5 years and been nice to it the whole time, keeping up with its needs.

engine: 150k ish. transmission: 72k

starting about 3 months ago, randomly one day the car began to do random misfires, at the beginning it would throw a p0300 but eventually stopped doing so while progressing to get worse. to explain deeper the misfire occurs most often at idle with AC turned off. with the AC on the rpms rev to 1000 and no longer misfire near as much. the misfire sounds like a ghost cam and is completely random. other symptoms have been car will stall if put in neutral while breaking hard only happened once so far but it was getting off the highway, it will just idle down to its own death. also when revving the engine to exactly 1100-1500 rpms and letting off the gas the car will stay revving for about 2 seconds before slowly returning to idle, and when doing so the idle will bounce. also to add, the misfire intensity seems to change randomly, somedays it'll be okay and the power feels amazing, others it feels terrible and super shaky, and feels like a Honda Fit would beat my *** in a race. now to list mods and things I've tried - also if you made it this far thank you for helping!

• Modifications
  

invidia n1 catback, Megan racing test pipes

Z1 short ram intake ported upper & lower manifold, Z1 Plenum Spacer 5/16''-1/2' (verified no leaks & did proper sealing)

75mm throttle body (throttle relearn completely with all accessories off)

Build CD009 put in recently

GTR injectors & walbrol 255

Add W1 Baffled Oil Catch Can V3.3

UpRev Tune 5 maps

• Things I've tried to fix this pain
  

replaced all coil packs & spark plugs

Intake leak test (pass I replaced all intake manifold gaskets as well)

Vacuum leak (pass)

Throttle body relearn (pass & done correctly)

Messed with the fuel pump & cleaned injectors fuel system is up to pressure (0.2 injector delay all running equal with AC on and off)

Tried various gas stations (running 93)

passed compression on all cylinders (170-177)

downstream o2 sensors are deleted and the tuner has disabled them upstream are fine.

cleaned all engine grounds + main terminals (14.9V cold start 14.3-14.7 warm)

visually inspected intake valves seemed okay and very clean

confirmed coil pack wires are secure

cleaned cam + crank sensor(s) and checked EVAP & PCV valve

properly cleaned + oiled the intake & cleaned the MAF sensor + swapped MAFs with a buddy just to confirm

disassembled VVT solenoids & cleaned them properly



I've consulted with my tuner & a Nissan master tech, and still have no clue

The last code the car ever threw was a p0011 bank 1 about a month ago, tuner looked into it and didn't see anything wrong with the fuel or timing. haven't seen any cel 1500+ miles since then.

 

Welcome aboard !
did you check the injectors