| So it has been some time since my initial post found: Here Actually if you have 4 small children like I do, it really hasn’t been that long. Anyway I still need help from the community. Since my last post, I have much to add. The problem still persists, and there is a clear noticeable misfire/exhaust popping when the engine has warmed up to temperature. I have checked so many things and I am exhausted of this. Here is a list of diagnosis updates:
• Performed boost leak test. Fixed two big leaks within intake tubing. System is now quite tight, with an extremely minor remaining leak (takes about 5 min to go from 5psi – 0 psi)
• New air regulator (source of leak)
• Checked for vacuum leaks everywhere (intake, injectors, hoses) with starting fluid and propane. No leaks found.
• Vacuum measured at idle is -18-20 in-Hg
• No fuel smell from engine.
• Verified IACV is working and adjusted. I have messed with this thing so much that I may need to replace it, as it has started act up every now again. Could this be a potential source?
• Changed left side O2 sensor. It was original to the car and functioning, but didn’t read the full voltage range. Right side is only about 10,000 miles old and works properly. Sensors cycle properly at 2k rpm.
• Cleaned all connectors : PTU, CAS, Fuel sensor, AAC, Air regulator, Coolant temp,
• Tested EGR and works properly
• Measured fuel pressure, no issues. Approximately 40 psi primed, and 37psi at idle. Pressure increases with rpm increase.
• Fuel pressure seems to hold for a long period of time after car is turned off. Probably takes 2-3 hours for it to go from 40psi to 5psi. To me this is indicative of properly sealed injectors.
• Measured resistance on all coil packs, and all at 1.1 ohms
• Re-measured all injectors and all are now at 12.4 ohms. Additionally, I stethoscoped each injector multiple times, and all sound functioning and virtually the same.
• O2 sensor readings indicate a possible problem left bank. Re-ran test after swapping spark plugs and coils to other side. Test result was the same. What is could this indicate? Graph
 Data Dump
 • Checked spark plugs after about 2 weeks of driving the car after the injector upgrade, and all looked appropriate. (Photo group 1). During the next 2 months of diagnosis, they have gotten worse looking with black deposits. I suppose it could be getting worse from all of the testing and not driving, (Photo group 2). (1-6, left to right) Photo Group 1
Photo Group 2
 • Disconnected MAF, and engine would barely run indicating that it is functioning.
• Ran power balance test. All cylinders had a drop with the middle cylinders being the least. Drop seems low to me for all cylinders. Cyl....RPM....Avg Drop
1.......690........50
2.......675........65
3.......694........46
4.......706........34
5.......685........55
6.......676........64 • Left side has significantly more moisture coming from exhaust. Now sure what this means, but it could be indicative of the richer condition in that side. 
Other notes to consider:
• The engine will sometimes run normal without misfire even when hot after it has been restarted. As soon as I rev the engine it will go back to the misfire problem.
• Misfire/popping only starts only as engine warms, and is super noticeable when hot (when the car settles down into full idle @750rpm). Misfire/popping is continues through all rpm’s. At this point, I am down to potential injector or harness issues which I doubt, or I got an incorrect/bum ECU upgrade from Ash. I have tried calling Ash so many times but he is very hard to catch. I suppose if I cant get a hold of him I may just order a Z1 or Specialty Z ECU. To me it comes down to what changed. I installed new injectors and ECU, everything else was virtually unchanged. Car ran perfect prior to upgrade. I am bound and determine to post my eventual fix, as I have reviewed too many posts that don’t fully follow up. The car is technically in winter storage now, but I want it back to happy days! -Thanks
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Update: Misfire issue continues, much more info… - 
