Jerking and hesitating at highway speeds

[Hagshollow]

I need help my 07 6.0L is having issues and no one including the dealership can figure it out. Not bringing up any codes but a number 7 contribution error and that doesn't even show up when the problem occurs. I will be driving down the highway and as soon as it kicks into overdrive the jerking and shaking starts the faster you go the worse it gets but only at a cruise if you step into it it's gone. I don't want to just keep throwing parts at I am not made of money. Does anyone have ideas?

[mhatlen]

Check the driveline carrier bearing first. Inspect the rubber webbing for damage, push driveline sideways and see if there is movement. If the carrier brg is bad it will shake the cab pretty bad and putting power to it will help it settle down.
When you throttle away from a stop sign you should also feel a sign of it shaking as well. It may be a injector but my truck had the same symptoms your describing and it only needed new u/joints and carrier bearing, and I only had 60K miles on it. 38" tires puts a lot of strain on the driveline and so does pulling heavy trailers, and I drive like a old lady so take a good look at u/joints and carrier brg.
If you do need to replace them make sure to buy domestic gresable parts.
Good Luck with it.........BTW did mine all 3 u/joints & bearing for under $100.00

[Hagshollow]

Thanks I will have to look at that. I just had all the bearings on the rear end replaced but something could of went wrong. I know what you mean I run 37's and it can be a lot on the truck.

[Tuscany]

Hate to say it but most of the time it's either ficm or injector related.