[450pirate]

Hello, I have a 2011 335i with the N55, aprox 92k miles, completely stock never tuned. Looking for a little direction on troubleshooting the issue I have, as firing off the parts cannon can get expensive.
Symptoms: After a cold start (sitting for 24 hours) the car has a rough idle for a few seconds. Rarely it will sputter and die. Sometimes I get a half check engine light. After that the car drives and starts normal all day long. Cranking time on a cold start seems to be normal, not long cranks.

-Leaking injector: This would make sense for my issue, however is the leaking injector causing a drop in fuel pressure and missfires on multiple cylinders during a cold start? Should I pull plugs after sitting and check for wet fuel in the cylinder?
-HPFP: do these sometimes give issues during cold starts? Should I log the fuel pressure?
-Rail pressure sensor: Possibly this giving an incorrect reading to the HPFP?
-LPFP loosing prime after sitting possibly?

I'm pretty mechanically inclined with a lot of tools, but I don't have a lot of experience with DI injection systems. I would really appreciate some advice from a pro on the troubleshooting direction from here! Thank you kindly!

[lookalikehuuh]

Step 1 as I see it based on these codes is to read the Hight Pressure fuel rail pressures. You have a code that suggest its stuck so we need to confirm that. High pressure rail pressures at idle should be around 600-700 PSI, once you go near the accelerator those pressures should up above that, preferably over 1000PSI. Full throttle should give you something in the range of 2000-3000 PSI.

If the rail pressures are not updating we need to fix that first because the car doesn't know what to do with the rest of the fuel system without that critical piece of information.