I have an '05 F150sc with 5.4 and auto tranny. From a dead stop when I accelerate I feel a slight shimmy/vibration. No other symptoms in normal driving. I only have 6800 miles on it. This p/u sits a lot and only gets <500 miles a month put on it. The vibration is felt mostly in my *** and only when starting from stopped. It seems to be getting worse but still not annoying.

 

If this is felt while accelerating pretty hard, you may have a pinion angle concern. There's a kit from Ford that has shims to adjust the pinion angle at the axle housing and at the center support bearing on trucks equipped with two piece driveshafts.

 

No, I don't get it under hard acceleration. Just when starting off normally.

 

Hm, pinion angle would still be the first thing I'd check. Mine shudders a bit on acceleration, hard or easy, and I know the pinion angle's off on it. Just another one of those things I haven't got around to fixing yet.

 

i agree mine has done this b4 till corrected

 

My 05 did that before I had the computer reflashed. I took it in to have it checked, they said they checked the line pressure in the trans. and said it was good. At that point in time there were no updates for the computer so I had to deal with it. I went back sometime later with a rough idle, they reflashed the computer and all has been fine since.