Engine: 70k boosted miles on a LE5

I think most of these could be related...where should I begin the troubleshooting?? Completely overwhelmed. I uploaded my tune so you guys can take a look.

Symptoms:
- Especially when the a/c is on, idle bounces around upon taking it out of gear (off load) and coasting to a stop
- Misfires most between 40-50mph under light load (-10,11,12 vac pressure)
- KR in boost @ 3800rpm or higher

Compression test results were 120 across the board. When not in boost, AFRs are fairly steady between 14.6-14.8. In boost, they seem ok but I don't hit it hard because I can't get rid of the KR.

Almost seems like the car won't hold it's tune. I'll tune it, it will run great for a week and then "learn" something and it slowly deteriorates to its current condition.

[ECM] P0101 - Mass Air Flow (MAF) Sensor Performance (Old) (History) (Immature)
[ECM] P0106 - Manifold Absolute Pressure (MAP) System Performance (Old) (History) (Immature)
[ECM] P0121 - TP Sensor Circuit Insufficient Activity (Old) (History) (Immature)
[ECM] P0172 - Fuel Trim System Rich Bank 1 (Old) (History) (Immature)
[ECM] P0300 - Engine Misfire Detected (Old) (Immature)
[ECM] P0420 - Catalyst System Low Efficiency (SES) (Old) (History) (Current) (Immature)
[ECM] P0442 - Evaporative Emission (EVAP) System Small Leak Detected (Old) (History) (Immature)
[ECM] P0101 - Mass Air Flow (MAF) Sensor Performance
[ECM] P0106 - Manifold Absolute Pressure (MAP) System Performance
[ECM] P0121 - TP Sensor Circuit Insufficient Activity
[ECM] P0172 - Fuel Trim System Rich Bank 1
[ECM] P0420 - Catalyst System Low Efficiency
[ECM] P0442 - Evaporative Emission (EVAP) System Small Leak Detected

 

test the maf and map sensor reference voltages for 5 volts respectively. I suspect your 5 volt bus in the ecm failed.

 

Is that something I can pull from the VCM Scanner or do I use the multimeter?

 

multimeter only

 

Yeah sous like this but if he is also tuned incorrectly he will throw most of thoses code but first check sensors. If maf is bad it can throw all thoses codes.