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Hello! AMFR stands for Air Mass Flow Rate. Basically, the code indicates that the computer is having to add/subrtract fuel as compared to what the Mass Air Flow meter says is coming in. This could be caused by vacuum leaks (from the intake gaskets or vacuum lines) or a faulty Mass Air Flow meter.
When we get problems like this in, we hook a smoke machine up to the intake, to help pinpoint vacuum leaks (if any). If you have a suitable scantool to monitor live data, you can spray around the intake manifold and vacuum lines/intake duct work with carb cleaner and watch for changes in the data. Sudden spikes in the adaptation values or O2 sensors indicate a leak.
If all that checks out OK, then you may have a faulty MAF sensor. The MAF sensor is also used as a load input, to help with transmission shifting, so a faulty MAF sensor could cause transmission issues, but without actually looking at the vehicle, these are only "possible" causes.