A few weeks ago I purchased a new intercooler for my 2010 Cooper S. https://www.amazon.com/Primecooling-Aluminum-Intercooler-Cooper-2006-2012/dp/B01KQ4FIJ2
A few days after the install, I began to notice a loss of power, and the rpms would start to build extremely slow around 5k-6k. I checked for fault codes and I got 002B5B (air flow sensor plausibility) and 002746 (multiplicative mixture adaptation). Cleared the codes, ran fine for 2 days. But the ckeck engine light came back and I recieved the loss of power once more. I continued to clear the codes for about 4 more days before we checked to see if the intercooler hose clamps were on tight. Turns out they weren't. Took it for a drive, still a loss of power. So I cleared the codes and its running fine, but now there is a loud hissing noise in the cabin whenever I accelerate, and the check engine light is back. There is also still an air flow sensor plausibility code. I'm at a loss at this point, and idea of what the issue could be?