I installed a new FMIC on my 2012 2.0 TSI the other week and since then she's receiving a P0101 (boost lag, turbo spikes, running rich / lean etc). The problem is that all these issues cleared up a day after driving with the CEL on the dash, which I can only assume means that the ECU was adjusting AFR based on memory (Revo Stage 2 SW). Once the error code is cleared though, these issues return for a while until the CEL pops back up and the car drives normally again. This carried on like normal over the course of a weekend.
The car is now experiencing all the aforementioned issues whether the CEL is displayed or not. I've checked all the boost pipes, replaced the MAF and although P0101 is not popping up any more, the car is still driving like an intermittent tractor. Boost lag, turbo spikes etc. It's as though under full or partial WOT, turbo spools and exhaust note loudens but the revs hang and all of a sudden the boost kicks in. DSG shifting does seem to hang around gears (mainly 2,3) before shifting. She drives a little smoother in manual mode but it's nothing compared to what she was before, she's still hesitant to change gears (almost like she's hunting) and power delivery is not instantaneous as it was before fitting the FMIC. I've cleaned the OEM MAF properly twice, cleaned the whole CAI, checked all connections etc. No other error codes are shown that could relate to coil packs, fuel rail, injectors etc. The constant alternating between running rich and lean I can understand due to incorrect data by the MAF but I don't see how this is still possible after a new MAF was fitted. I have run out of ideas. The only other issue I can think of would be the MAP sensor but if that was experiencing any issues, surely she should pop a CEL too..
I've changed many FMIC's before in the past and I always triple check everything but this is the first time I've run into an issue like this
Any thoughts would be appreciated!
