Vibration when starting 4.6
I have a 2006 4.6 f150.
I've had it for 2 months now. When I first start the truck, about 10 or 15 seconds after starting,I hear a vibrating noise on the driver side of the engine.
Today, I popped the hood before starting and noticed the vibration is coming from the air box area. I put my hand on top of the air box and it was vibrating away. It only does it for about 10 seconds or so then quiets down. It may start again until the temp is in the mid range, after that it stops completely.
I just put a new air filter in it a few days ago. Also, I've been running ethanol free gas. Other than that, once it's warmed up, it runs great.
The truck only has 87000 on it and has been well taken care of.
I've used ethanol free gas in other vehicles without any problems. Not sure if the problem started shortly after running this fuel.
Any input would be greatly appreciated.



