Actually you are real close to it (bg).
Where my story has pertenance to your case is my thoughts that you are describing an AMM failure; could even be the hose (something I might not of considered last week). The real key to diagnostics are the adaptation values. In most AMM failures the compensation is off the scale and is one of the codes.
I can tell you from personal experience that a lean AMM will cause misfire codes and this is real misleading, if one is diagnosing using codes.
After the fact, I can point to how the adaptation values in my case should have told me what was wrong (actually they did). Since they were both perfect (LP at 1.01) and at fault (adaptation fault codes P0170 and P0173) a loose hose was one of the possible answers.
Bosch Master, ASE Master, L1
33 years MB technician