I have a 200 f150 with the 5.4 V8. It has been idleing really bad at stop lights and almost stalls out. The RPMs drop to 400 when I slow down. I replaced the IAC a few months ago and it is still clean as a whistle when I took it off. I got the trouble code P0174 and cleaned the MAF to clear the code. Then got P0074 for Ambient Air Temperature Sensor. I am not sure what this is or how it effects my idle problems. I also put in a K&N intake system not too long ago.