question on my ranger's engine
 

i love my 150 more than anything but my ranger is what i use for work. that being said i have 237000 miles on it and it pretty much runs like a champ. however i have a cel p1151 manufacturers controlled air and fuel sensor or something like that. sometimes it has a chitty idle like after i've been driving for a bit and come to a light, as im sitting there it acts like it wants to just give up and die. it was doing the same thing about 80,000 miles ago and i changed my iac and it did the trick. well i did it again and its still doin it. mas sensor is pretty new as well as o2 sensors. would the pcv have anything to do with this?
thanks in advance to any tips, you guys and this site rock :rocker:

Explanation and normal fixes:
http://www.obd-codes.com/trouble_codes/ford/p1151.php

Hope this is useful info.