نصب نادرست فیلتر هوا

The air filter seated wrongly in its housing, so air bypasses it. Unfiltered air reaching the engine carries dust straight onto the airflow sensor's element and into the bore, which is what makes a fitting error a diagnostic fault rather than a housekeeping one.

A sensor coated with dust under-reports airflow, so the mixture goes lean and the codes name metering. The filter itself looks fine — it is in the housing, it is clean, and nothing suggests it is not sealing. Check the filter seats squarely on its face all the way round and that the housing's clips are all engaged; a lid closed on a filter sitting proud leaves a gap that is invisible once shut. Suspect it after any service, since this is entirely self-inflicted.