"07" F250, 4x4, 48000 miles. Occasional buck or feels like abs is applying rear brakes real quick for only a second. Only does it with the cruise on @ around 76 to 78 mph on a long down hill stretch. One time the abs light came on but only one time and it went off when I stopped at the next rest stop and turned the truck off. It didn't come back on but the same bucking happened again twice over the next 200 miles. Any idea what's going on?

 

Just wild guesses for me, but if you jack up rear end, on both sides, in neutral with front wheels blocked, can you freely spin rear wheels, is ebrake catching a bit, other possibility is are your caliper pins lubed on all four corners. No way ABS is doing anything, but these are possibilities. Also, is your cruise engaging properly, brake shuts off, can set cruise, increase speed, descrease speed ok, might be something wrong that needs to have codes read. Its also possibly recent brake work? Perhaps not bled well, abs needs to be excersized when bleeding to get all air out.
Maybe someone else has something more specific, one of the techs ever seen this?
O/o

 

are you in tow/haul mode or not??

 

Not this time when it happened, I wasn't pulling anything. But it has done it in the past pulling a 9200 lb. trailer while in tow haul mode, but that time it bucked and deactivated the cruise control.

 

Most of the Ford solutions for a buck/jerk condition have been to upgrade your computer programs (PCM, FICM and TCM), but this has usually been on older models. You may still be in warranty on this (but at a $100 deductible) - you should have a 60k drive train warranty.

What ever happened on your oil consumption problem from 2007? Still losing oil? If you are, and you are burning it, a lot of things can "coke up". Turbo vanes sticking comes to mind, not to mention EGR system.

Also - do you have the factory tow-command or any aftermarket brake controller?