Truck slowed down the died going down the road

OK I was driving down the hwy and had my cruise
control on like I do every day and ive been hearing
a small huming noise lately not loud but real soft I
was thinking it might have been the radio but I
know this wasn't what caused my problem. I was
going down the hwy doing about 65 mph when I
felt my truck bump like someone taped the brake
real fast and let off my truck started to gradually
slow down even if I was pushing on the gas it
didn't go any faster it finally came to a stop my
lights dimmed then the truck died. I sat puzzled
thinking it might be the altenator but I started it
with the key gave it a little gas and it started back
up. It was changing gears while going down the
road so I don't think it's my transmission  and I
don't think that would cause a truck to die
completely. But I anyways I drove a few more
miles and it did the same thing again. I made it
home checked the engine nothing smoking or
burning. And checked underneath the truck
nothing leaking. I even hooked up my obd1 and it
gave me the code 11 everything's ok. So Im not
sure what it is could an alternator do this or a
starter?? Any help would be greatly appreciated.