P2177 after EGR replacement

[peter.sellers]

Did an EGR replacement recently because of P0401. The original EGR's stepper motor had died. The replacement removed P0401 and everything was fine until I boosted hard last week. This was after one week of driving with the new EGR and no codes. And now I am seeing P2177 (STFT is -2 and LTFT is ~18). Looks like it is pretty lean considering the upper limit is 25. Also looks like the ecu is learning and trying to bridge the gap between STFT and LTFT (?)

Based on what I have researched-

- I am going to stay out of boost, run up to 3K rpm in low gears and decel to see if there is any vacuum build up
- check MAF and see if it is gunked up
- check for leaks from intake to turbo

Any other recommendations of what to do and where to look? BTW, I am learning about this as I go along since it is new to me.

The car is 07 MS3 w/Cobb SRI, Forge BPV. Thanks in advance!

 

[MSMS3]

It is most likely pulling in air through a vacuum line or hose involving a connection between your MAF housing and the turbo. Check the TIP connection on both ends -- to your MAF housing and to the turbo. Check all vacuum lines to and from the TIP including the lines on the electronic boost control solenoid and on the BPV valve and the recirc tube. Raw air is getting pulled in somewhere. Not only is this causing a lean condition, but that raw, unfiltered air is full of dust and other fine abrasive particles that will harm your engine. There are other possible causes, but my bet is that you did not get everything buttoned up tight after your EGR work.