Cobb - Fuel Trim / O2 diagnostic help please....

I in need of help diagnosing my fuel trim problems for my 07 335i. This is a real tough one to solve. The dealer has given up on this. I have a few idea but would appreciate any feed back on the attached logs. My fuel trim seem to go wild when boost is around -3 to 0 PSI going by the logs but can read to much into this. The are constantly osculating. At WOT the car settle since its in open loop but it on stage 2+ drive map. The logs show the fuel system is good but drops in pressure a bit when fuel trims go +30% so expected. The 02 sensor look just crazy so not sure if this is normal or both are failing at the same time. I am guessing this is the issue. The car should throw a code but trims never stay constant more than a second. The car drives fine and you wouldn't be able to tell there is a probe which is the most frustrating part

So far the over the last two months the following has been serviced:

- charge pipe replaced
- Tmap & Map sensors replaced
- Valve cover and PVC system replaced
- Intake system Air leak check with smoke machine and pressurizing (Checked twice now)
- Exhaust leak check twice
- Vacuum system fully replaced including solenoids
- Fuel system diagnostic check
- 02 sensor checked for installation and plugged into the right connector

The attach picks are:

Boost vs. total fuel trim (ST+LT) on Bank 1
Lambda Req Bank 1 vs. Lambda Bank 1
Lambda Req Bank 2 vs. Lambda Bank 2

If anyone has comments on the logs that could help out with this problem it would be much appreciated. I don't have a good baseline to compare the data so comments about this would be helpful...thanks.

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Attached Files

• BB.zip (1.46 MB)