P0174+P3027

[kboolin37]

System too lean (Bank 2)
HO2S 1 Bank 2 Operating Temperature Malfunction

G-Power M3

Car was sitting for about 3 weeks while on vacation. Tons of mods and forgot to hook up a trickle charger, (air suspension perma pulls from battery). Car was completely dead when I got back home and rough idled+stalled itself when started, it was not throwing any codes what so ever. Eventually some time goes by, take it to a shop I trust and does BMWs primarily. Everything from scanner reads within parameters and no codes show up, find out Battery Distribution Box is faulty, replace it then they tell me to drive it and see if anything pops up.

Drove fine under boost and full throttle, but didn't like "cruising" at the same speed or idling, would be semi rough or sound "off/wrong". Eventually car would act like it is in limp mode and sounded like it was misfiring but was not, would not full throttle anymore and started lightly shaking when under load, would only build boost if you drop the clutch. Never actually went into limp mode, but felt exactly like it.

Trying to figure this out but struggling, have another E92 M3 and never had any issue like this, and that car has 120k miles, this one has 40k. So far what I have had recommended is it could be Throttle actuator, Intake actuator, idle control system, or a vacuum leak.

Curious if anyone has any insights or any quick checks I can do.