I think you are smelling the coolant that is soaked into the carpet on the right front floor board.
When the heater core leaks on the mirage it tends to drain out of the HVAC case onto the right front carpet.
This is based on the two mirages we had at the shop for this issue! And your case is the first on this forum I heard of.
The second of the two mirages we had was not obviously leaking like the first one (which was dumping) but you could smell it and swipe a finger on the carpet and get slime (coolant) on the fingertips. So it had to been slowly dripping on it.
And yes both were 14s like your car. (and mine darn it)
I would check the carpet and if it still has residual coolant in it,see if it could be cleaned somehow to get rid of the smell!
@Cobrajet: Yes the entire dash has to come out to get the HVAC case out and then the heater core can slide out to the left.
View my fuel log 2014 Mirage DE 1.2 manual: 66.3 mpg (US) ... 28.2 km/L ... 3.5 L/100 km ... 79.7 mpg (Imp)