Are you sure that the heater plugs are working? Put a meter from ground to the plug supply. Before you start it in a morning, pump the bulb on the drivers side engine mount. It should go solid within one pump. If not then you have an air leak.
Mine used to smoke because one of the oil pipes on the engine were blocked (and it was blocked inside the engine)..but I had an older engine... I know this is unlikely on your younger car....but its a suggestion
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