Low mph shutter
 

Need help. I have an 01 f150 that i have replaced the control arms, lower ball joints, sway bar end links, pitman arm, idler arm, inner and outer bearings (front), tie rods and had it aligned, I also replaced my intake manifold, valve cover gaskets, coil packs, plugs, and replaced a bad injector along with some dry rotted vacuum hoses. At about 10 mph my truck shutters and levels back out at around 25-30 mph any ideas as to what may be causing this?

Did you check the U-joints ?

Not as of yet, I have them just haven't had time to replace them

I know this sounds silly but have u checked your pulleys?