extremely bad vibrating
 

On the highway between about 60 mph and 72 mph i get terrible vibrating on my 99 5.4L xlt triton V8 . its way worse coasting then accelerating, ive popped it into neutral and it still does it so this tells me its not the automatic transmission but i have absolutely no idea what could be wrong ive heard different things from different people im just wondering what you guys think is the problem here. my bud dan who thinks he knows everything about cars always makes fun of me and says thank you for the message chair, so id like to shut him up. any help would be appreciated, thanks.

There's a number of things it could be.

Tires out of balance (easy fix)
Warped rotors (bad vibration while braking)
Ball joints worn (cause tires to wear improper)
Tie rod ends worn (cause tires to wear improper)
Wheel bearings worn (they would probably "hum")
Driveshaft out of balance (bad vibration)

You might check those out, in that order.

u-joints

It's going to be a tire problem more than likely. Make sure the tread depth is equal left to right on all of your tires. You can't play it by ear either, check it with a ruler. That will tell you what the problem is and what needs to be adjusted. If they are worn too bad, you might as well look to invest in a new set, especially on the front end.

i know the tires are balanced because everything was fine about 2 months ago and nothings changed the weights are right where they used to be.
it cant be the rotors because it vibrates when im not braking ill just be coasting and my whole truck vibrates.
i just had my upper and lowers replaced so it cant be that
i dont know how to check for tie rod ends or driveshaft being out of balance but ill see if i can get a mechanic to check it out.
my uncle says it could be the U-joints would you know anything about that?

have you been off-roading lately? I had the same thing last summer. When I got on the highway to come home it vibrated. and I found out, it wasnt anything but some mud that got on the inside of the wheel and "stuff" and caused it to vibrate.

yea actually i went mudding. real bad idea my truck is completely stock i got stuck my frame resting on the middle of the rut so my tires werent even touching the ground for 4 hours, a come-along plus 5 guys, a ranger, and 2 jeeps couldnt do the trick untill a 2500 duramax diesel finally pulled me out. son of a *****. but that could be it the vibrating started soon after now that i think about it. my question is why wouldnt it do that consistantly throughout the range of speed not just 60 to 70.

ya check up under there. and wash her real good. and see if any of that helps.

alright thanks for the help i apreciate it.

no problemo. just savin you money. and if that dont check out...then you might want to get it checked. be sure to keep us updated.