Out of the blue wouldnt idle

This morning my f150 5.4 2001 started like everyday died immediately.Held foot on gas for min then idles very weak.Drove it anyway had to keep foot on gas at all stops finally it started smoothening out some.End of day ran fine.Fuel pressure seems strong it ran perfect as long as on gas.Have noticed before once in a great while when ive let off gas driving it has felt like downshifting but never ammounted to anything. Anything i should chek obvious?

First thing to look at is the Idle Air Control valve. This is your "choke" on newer vehicles.

Ok is the idle air control valve on side of throttle body two screws into body and has plug ? Or is that throttle position sensor

It isn't the sensor,it looks like a tube and when you take it off there will be two somewhat large holes in it. I would clean the throttlebody first.

It will look something like one of the pictures below. You can try cleaning the throttle body, but if you have not had a nagging problem with idling, more than likely the IAC has decided to quit.

http://usera.ImageCave.com/way2old/iac.jpghttp://usera.ImageCave.com/way2old/idlemotor.jpg

thanks guys.cleaned it so far so good