I have a 2004 F150 xlt heritage with 32,000 kms. When I am in park and idling the engine runs smooth, but when I go for a drive and come to a stop at a light I get a vibration in the cab. When I continue to drive no vibration. Could this be a low octane fuel prolem? I have a 4.6l triton engine.

 

Sounds like a IAC problem. Do a search, this is starting to show up alot lately. Must be the extreme heat

 

Mine was the EGR valve but I have 250K miles. I would try a basic tuneup. Airfilter, clean air flow sensor and intake throttle valve and check for a vac leak. Its cheap and could not hurt. Also when did you change the fuel filter last? Bad gas? This is where I usually start at the basics.