Hey guys I'm new to this forum and was wondering if someone can help me out. I drive a 97 f150 4.6 and the truck idles a little rough when in park or stopped. It drives pretty smooth but when I'm at a light I can feel it, when I have groceries in the passenger seat u can see the plastic bags vibrating, best way I can describe it. My gf says I'm nuts but I drive the truck everyday therefor know it in and out. Some people I've talked to said its a normal thing. Is this true? The spark plugs are good, along with the coil pack (brand new actually) maybe the IAC valve? Dirty MAF? Maybe there's build up on the fuel injectors. I don't know. Anyway any thoughts on this would be appreciated.

 

I've been chasing my light vibration at idle for over a year now. Can't figure it out. I'm pretty set on it being normal (lots of research seems to agree with this). I've tried replacing/cleaning all your above mentioned items. Also have checked for vacuum leaks. Unless there is a slight intake gasket leak or something I can't find.