V8,
i am also dealing with the notrious bucking f-series. After reading posts on this for days, i have concluded that it is the fuel injectors clogging up. With the egr putting the normal amount of exhaust into the intake and the clogged fuel injectors puttiing in less gas, you get the bucking and stumbling. restricting the egr will solve the problem, but it is only compensating for the lack of fuel. The injectors need to be serviced. take it to a shop and have them cleaned. don't let them tell you you need new ones. Personally, i put half a quart of ATF into half a tank of gas and am going to run it out. ATF has some pretty hefty detergents in it that should do the trick. I'll post the results.