Vortex

Cleaned the Mass Air Flow sensor following YouTube videos - no difference

Tried tapping IAC with ratchet while it was idling high - no difference

Next step - spray hoses and IAC as JBrew rec'd or just replace IAC (motor craft part in hand)

Vortex

Also seems to happen just as much on CNG...and moreso when it's hot out (definitely on 95-100+ days out in Vegas)

RangoWA

Do you not have a OBDII scanner? That could help a bunch.

PerryB

My money is on the IAC. My son's '01/5.4 was doing the same thing and a new IAC fixed it.