My 2000 F-150 5.4L (62k miles) will not idle when cold, sometimes it's fine and sometimes it just will not idle and cuts off at first startup in the morning or after sitting for a few hours. I cleaned the throttle body with carb cleaner but it didn't help. It doesn't give me a check engine light and today after it warmed up the idle was low, about 500 rpm and not real smooth. seems like it used to idle around 700 or so. On the way home i kicked it in the ass and ran it up to about 5000 rpm, when I got home it was idling fine, but I bet it comes back in the morning.