1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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17,289 Posts
Welcome to Allpar. Proper motor mount adjustment is important. Verify that no metal-to-metal contact is transmitting engine vibration into the body when the A/C is engaged.
Another possibility is that the compressor is dragging and adding excessive load to the engine at idle. This can be from an over-oiled/over-charged A/C system or a failing compressor.
You ask about a fan motor fault, is there one present? Without a fan motor cooling the condenser, the high side refrigerant pressure will skyrocket at a stop and load the compressor, which will in turn, load the engine making for a slower, rougher idle.
Another possibility is that the compressor is dragging and adding excessive load to the engine at idle. This can be from an over-oiled/over-charged A/C system or a failing compressor.
You ask about a fan motor fault, is there one present? Without a fan motor cooling the condenser, the high side refrigerant pressure will skyrocket at a stop and load the compressor, which will in turn, load the engine making for a slower, rougher idle.