i was told not to clean the IAC. 2 reasons, one the "film" they coat the inside with will wear off with a cleaning, especially with a toothbrush. two if you have moosing it will make it louder and or create the moosing which makes sence. if cleaning is your choice id suggest to clean it quite often, with the "film" gone it will clog up faster. Mine was moosing like hell and stalling every 10 times or so that i put the clutch in, it was really bad. i read a thread on some cougar site, that gave a picture of a mondeo in europe (i believe) that too the stock vacume lines out and replaced it with 3 foot of heater hose from the port of the IAC right to the vacume line on the intake. i believe the opening is 7/8. i do have a pic somewhere.i posted this before you probally can find it in the search somewhere. about 2 months ago or so. i used a braded hose to replace the stock vacume lines, which is a cluster fk** to begin with. it looked very much cleaner with braded hose in there. and never had such problems again. if you need more help id be glad, but i need to find the pic. it explains it best.
