Can you help with my DTC code stew please?

Hi Guys,



I got a P0411 a while ago and it was the notorious combi-valve hose.



That was late last year. It was the only DTC I've ever had with this car. I haven't had any issues since then..........until now.



Between then and now - as preventive maintenance only - I've replaced all vacuum hoses, vacuum check valves (yes they're facing the right direction). I've seafoamed, installed a high flow drop in air filter and stainless muffler, fuel filter, spark plugs, vacuum/boost gauge, crankshaft positioning sensor and cleaned the throttle body (with carb cleaner) and the MAF (with MAF cleaner).



Everything is tip top, but apparently not, because the car is now consistently throwing the following codes:



Faults Found:

16795 - Secondary Air Injection System: Incorrect Flow Detected

P0411 - 35-00 - -

17544 - Fuel Trim: Bank 1 (Add): System too Lean

P1136 - 35-10 - Please Register/Activate - Intermittent

16684 - Random/Multiple Cylinder Misfire Detected

P0300 - 35-10 - - - Intermittent

16685 - Cylinder 1 Misfire Detected

P0301 - 35-10 - Please Register/Activate - Intermittent

16687 - Cylinder 3 Misfire Detected

P0303 - 35-10 - Please Register/Activate - Intermittent

16688 - Cylinder 4: Misfire Detected

P0304 - 35-10 - - - Intermittent

16825 - EVAP Emission Control Sys: Incorrect Flow

P0441 - 35-10 - Please Register/Activate - Intermittent

16686 - Cylinder 2 Misfire Detected

P0302 - 35-10 - Please Register/Activate - Intermittent





I know I don't have a vacuum leak.



I just checked the purge valve and it seems fine (I can't blow through it).



I have a new fuel filter.



I have a new FPR vacuum hose.



There is obviously a common thread here. I just can't figure it out.



I'm out of ideas. Can anyone help please?



Thanks in advance!