...the 2 small metal pins ... What do u mean by 'pins'?
The cleanup should be on components in the airflow (behind the meshes) as MAF has been dismantled. The heater element & sensor do oxidize, and collect dust, degrading component performance. Oxidized = lowered performance heating will result in lean (pwr loss) injection... Electronic cleaner may make a big difference on the heater efficiency. My cleanup of the over 10yr old, 85k, MAF resulted in significant total pwr increase.
Cleaned 3gen MAF resistor (in front): see
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If you re-installed MAF and its not fitting correctly; even very small leak will cause idle fluctuation. Reseat, retighten all tubings... Also electrical connectors should be cleaned, you may also add contact di-electric grease on contact pins.
Measure your MAF output voltage, idle should be steady 1.2 -
1.8V... see FSM page EC-169. You may find that page by clicking via 'top left Favorite Links' - see below.
The MAF component characteristics have now changed. This may be a situation where ECU settins have to be reset (batt off over 30min or via tester). After reset, there is a certain 'training' period where ECU optimizes for swapped components (as they always are slightly different). Read the FSM for this lengthy issue...