SYMPTOM: On smooth blacktop truck feels like I'm driving on washboard or rumple strips. The whole truck literally shakes.
Specs: 2004 F-150 Super Crew short bed Lariat package. 9K miles
The problem happens almost exclusively in the first hour of driving. After everything is warmed up the symptom doesn't seem to appear, but not enough evidence to state that conclusively.
Can occur at almost any speed and at any condition (so far as I can tell)
It happens when the tranny is in Drive 2x (only because that is 99.9% of my driving)
It continues to happen when I switch to neutral and 4x4 High.
It continues to happen if I turn off the engine.
It continues to happen if I jam on the brakes and stop.
It continues to happen if I steer in a tight circle left or right.
The tires are in good shape (the problem seems to be only marginally speed dependent) in other words it only happens when I am moving, but it doesn't seem to get progressively worse with higher speeds)
It often, but not always, goes away after I pull over and stop briefly (that didn't work this morning until I did it a few times); but that could be coincidental because it will also just go away if I keep driving, I just don't want to keep driving because the truck will eventually fall apart if I do.
I've seen some descriptions of F150 shakes in this group, but nothing that really matches my problem.
I'm going to bring it into the dealer this week, but I was hoping for some insight before I have to do battle with the Service Manager because of the 'intermittent' nature of this problem.
Any thoughts, insights or suggestions (except 'buy a GMC', my wife already suggested that) would be greatly appreciated.