A lot of times whenever I put my f150 in park or sometimes when I slow down
at a red light my rpm's go to swinging just a little before it steadys out. It acts like its hunting for a good idle point. Does anybody have an idea what could be causing this? I swings about 300 rpm's either way.

 

search CLEANING IAC.(idle control valve) also check for vac leaks and might want to search CLEANING THROTTLE body. this should get you the results you need. we have all had this so dont worry

 

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