Hello guys, my GTI is weird after I cleaned the O2 sensors connectors. At first, it was really rich at idle, like 0,65-0,7 lambda (I have an Aftermarket O2 reader installed). Now that I simply disconnected and reconnected the O2 sensors it barely can idle after it is warmed up. The car is far from stock, with a custom remap and catless downpipe. Also, the after-cat O2 sensor is malfunctioning and giving DTCs. The weird part is that the Additive and Multiplicative Lambda correction values are stuck at 0 when logged with VCDS. The front O2 sensor is reading accurately, but the car does not correct values. I wonder what is happening. Would a bad after cat O2 sensor cause this? I'll post here the log file to show how the O2 sensor reading oscillates on idle and how the Lambda correction is stuck at 0. If anyone could shine a light on this problem, I'd be very thankful. If I let any information unknown let me know. I also have the .BIN file for my map, so I might answer tune-specific questions.
Why would the ECU not be doing closed-loop corrections? The car tries to stay at idle, but then Lambda goes to 1.3, so it enriches and this keeps going in a cycle

PS: I've replaced my MAF sensor, so dismiss the error code.

Thanks for the tips. The MAF error have been fixed, I got a new MAF sensor. I'll try the boost leak check

Pressure test the entire intake from the turbo inlet without disconnecting anything, and you will find out.

Here is a LOG showing how the O2 adaptation keeps changing like crazy