TYPE OF STUTTER/STUMBLE
Steady throttle/Increasing throttle/Both:Light throttle from 1500-4000 rpm, idle
MODS
Intake:K&N drop in filter
Exhaust:3" catless downpipe, catless uppipe
Fuel:stock
Turbo:stock
Engine Management:stock
Tuner and revision of tune(if you don't mind):Cryotune Performance E-Tune, rev 4 (I think)
MAINTENANCE
Sensors changed:cleaned maf, checked wastegate solenoid function, front O2 changed last year
Plugs changed:Plugs and gap checked, normal
Coil Packs changed:stock
OTHER SYMPTOMS
Check Engine Light:none
Etc:car feels slowish to build boost, but this mostly went away from fixing a pre turbo exhaust leak
RESULTS
What has and hasn't worked for you:JB welded the stock TMIC after one of the end tanks was leaking and got a new BPV gasket. Stumbles and idle got slightly better. Fixed pre turbo exhaust leaks via new gaskets and car is more quiet and seems to idle smoother, however light throttle jerkiness is still there. I have boost leak tested, checked TGV gaskets, TB hose seals and they are holding. The car seems to hold boost. The MAF scaling is correct from my logs and the car doesn't have any obvious points that stick out from logs. IAM is at a constant 1, knock count is ~1 per 20 minute drive, no FLKC or ignition is being pulled.
If something worked, how long has it been working for: The exhaust leaks seemed to fix the boost issues, however the car still has occasional studders / misfires at idle and is jerky under low load, light throttle.
I really want to figure this stuff out. I'm going to try to clean the TB with TB cleaner, then put new plugs in (I have a new set). If that doesn't work, check injectors, coil packs, etc. Why can't it just drive smoothly? It could be a tuning issue but the car ran great right after the tune.
Edit 1 - update: I installed a boost guage. Car hits target boost fine and holds boost well. Spools fast. However, only pulling 15-16 inhg of vacuum at idle. My thoughts are post maf pre turbo boost leak. I'll check the inlet later.