Apparatus and associated systems, methods and computer program products relate to monitoring the performance of an operating gas meter by automatic and substantially continuous differential pressure (dP) measurement. Measured dP may be compared against a baseline dP characteristic to determine if the measured dP exceeds a threshold value above a baseline dP characteristic. If the threshold is exceeded, then the system may generate a signal to request repair or replacement of the meter. After installation, some embodiments collect dP data over time and/or over a range of flow rates to automatically learn a baseline dP characteristic under installation conditions. A system may switch from a default baseline dP characteristic to a learned baseline dP characteristic. Some embodiments may further correct volume or flow rate signals for line pressure and/or temperature. Further embodiments provide a passive apparatus to protect a dP sensor against transients in line pressure and/or differential pressure.