Lee, that type of fault is what I classify as a “perceived airflow issue”. The ecu is telling you as much by logging a code for implausible map. If you think about it, anything that can influence airflow can change the map value and so can cause that code. It doesn’t need to change much for the ecu to be unhappy. The map value you measured may look right but could be slightly out. Ask yourself how the ecu decides what the map value should be.