N55 lean codes thrown and strange behavior after stop and go traffic

[Baileyboo]

Hello all,

Looking for some advice pointers or inspection point. I installed a reman engine, pure stage 2 turbo, dorch engineering HPFP and full bolt ons. Drove the car for a month to break in the engine and no engine codes thrown and smooth power.

A few days ago the car sat in stop and go traffic for the first time about 20 minutes after running it up to redline earlier in the same drive. After sitting in the traffic the car started stumbling terribly at any RPMs over 2500. Got the car off the freeway into a parking lot and turned off the car. Let it sit for 15 minutes then started the car and immediately died after running very rough. Got it started by giving it more gas but ran very rough at higher rpms, got it home under 2500 rpms.

A few hours later I took the car out again and was running better but stumbling when I was hitting RPMs in the 5500+. This is when it hit 2BEA (mixture control: fuel-air mixture too lean, large deviation) and 2C42 (Mixture control: multiple fault) codes.

After reading up on the codes this seems like it has a few causes. One un-metered air coming into the system or a problem with the fuel delivery.

My plan is to smoke test the intake.


Questions I came up with.
-Any part of the system i am overlooking?
-Has anyone experience strange sumbling after stop and go traffic?
-Is there a way to bench test the LPFP?
-Is there a way to purge vapor from the fuel system?
Is there anything else I can check