Just got done with the run around on this one:
'06 F-250, 4x4 Auto, 6.0L (of course, 6000 miles.
When the truck is cold there is a very distinct vibration or stutter at around 45 - 50 MPH. Basically as soon as the trans shifts to OD and the TCC engages it comes right in. Drop out the TCC or pop it down a gear, gone. I took a number of recordings, and the problem is definately in the motor - you can actually watch the RPMs dither, as well as the ICP and IPR.
I replaced the VGT solonoid and supply tube, as per hotlines recomendation (Zinc contamination), and no change.
If I take control of the IPR, the VGT, etc. nothing changes unless I bump the IPR up 1 notch.
EGR is 0% during the entire event - too cold?
Finally I tried 2 other 05 / 06's we had here (4K and 22K miles) and they both also seem to have the condition? The newer truck not as bad, but the TCC isn't kicking in the same on it, adaptives aren't set apparently.
I shipped all the recordings to Ford, with their final thoughts that it is a normal condition.
I suppose I should just take them at that, but I've never had anyone complain of this before - mostly just curious if this is elsewhere? /forums/images/%%GRAEMLIN_URL%%/shrug.gif
Thanks guys!