[vktr3]

Began watching the ST/LT FT on my '06 325i in an attempt to diagnose ongoing high oil consumption, surging cold starts, and occasional random misfires noticed while stopped at lights.

Fuel trims on 06/08/18 at idle after a 30 minute mixed highway/city drive were:

RPM : 656
STFT 1 : 3.1
STFT 2 : 5.5
LTFT 1 : -3.1
LTFT 2 : -10.2
MAF : .447 lb/min

Notes:
+ while commuting the LTFTs dropped
+ during my morning commute temp was ~ 70° F
+ coolant temp ranged between 200° ~ 212° F (seems a little high but I don't know spec off the top of my head)
+ interesting to note that on my scanner when watching B1S2, B2S2 O2 voltages B2S2 took longer to drop back down after the engine was shut off than B1S2. Could be screen refresh delay or lazy downstream O2 sensor... I wouldn't be surprised as all O2 sensors save 1 upstream are original and should probably be replaced.
+ K&N air filter recently reoiled
+ oil/filter change in april
+ spark plugs changed last year (old ones looked ok upon inspection)
+ engine has 235k miles
+ owned since 2009 with most maintenance done by yours truly

* Early thoughts :
MAF sensor problem, high fuel pressure, leaking fuel pressure regulator, faulty evaporative emissions components, leaking injectors, defective O2 sensors, exhaust leaks/pinholes before the O2 sensor, coolant temp sensor, and base engine issues such as low compression and incorrect camshaft timing.

[vktr3]

** UPDATE **
Went out to my trusty ride (second owner since 2009) and took some readings at lunch time (1245). Ambient temp ~80 F, sunny.

On start
STFT 1 : varied between -.8 -> 4.7 until loop closed
STFT 2 : varied between -.8 -> 4.7 until loop closed
LTFT 1 : -4.7
LTFT 2 : started at -10.2 then decreased to -7.8
ETC : 117 F
B1/B2S2 - .425v until loop closed
RPM : ~925 until loop closed (guessing. B1/B2S2 readings were on different screens. will verify this with next test. vibration change from rpm drop seemed to coincide with change in S2 voltage change)

RPMS at ~3k for 1 minute
STFT 1 : .8
STFT 2 : .8
LTFT 1 : -5.5
LTFT 2 : -6.3
ETC : 138 F

Idle post 3k RPM
STFT 1 : 5.5
STFT 2: 5.5
LTFT 1 : -3.9
LTFT 2 : -9.4
ETC : 163 F
B1S2 : .65V
B2S2 : .76V

* NOTE
+ misfire as RPM settled after 3k RPM test
+ attempted supposed throttle body reset (key in, dash lights on from start button push without brake pedal, gas pedal to floor for 5 sec, dash lights out after start button push, release gas pedal)

* EDIT
Next steps :
+ INPA to reset adaptations
+ Inspect MAF connector (harness side) for any anomalies

[vktr3]

** Update **

Reset Throttle, Lambda, and VANOS adaptations on Saturday and then go for a nice lengthy drive with plenty highway/back road and city driving. This seems to have had some positive results on the long term fuel trims!

At idle post 30 minute commute

STFT 1 : -1.6
STFT 2: -4.7
LTFT 1 : -3.1
LTFT 2 : -4.7
ETC : 207 F
B1S2 : .76V
B2S2 : .765V

The STFTs seem sort of erratic now. Could be the refresh rate of the scanner screen but sometimes at a stop light they'll flop around fairly close to 0 but other times they'll stray a bit further from 0. I'm curious if this adaptation reset will have any long term effect on my fuel efficiency. The majority of my daily commute is highway where I'll cruise between 75-80 mph and get 23.7 mpg reported by the car.