I was having an idle problem and then I added berrymans b-12 and 3/4 of a tank later I am having the current issue with the idle which is much worse.
I Did change the MAF about six months ago, had a code, then changed it. Code gone idle stay the same.
I just went to the ford dealer and they said $11 for the IAC gasket, seems a little to expensive.
Where in Canada are you from?