[choo]

Just bought a 99 suburban . It has a pulsating vibration when driving between about 40 to 50 mph only when my foots on the accelerator to hold a steady speed . I took it out of overdrive put it in 3rd still does it but alittle less intense . Feels almost like the vibrations you get pulling onto the shoulder of highway.

 

[Pete95Sierra]

get your front end checked out...... your gonna need new ball joints and possibly wheel bearings and to get your front wheels alligned....

 

[choo]

I replaced the wheelbearings and checked everthing else while I was down there . the steering is strait and smooth even when it vibrates , I've had vehicles in the past with front end problems its not up there . I cant pin point where the vibrations start they resonate through the whole truck . but thanks for the advise :money:

 

[84fiero123]

If it did it all the time at that speed I would say tires out of balance.

But because it stops when you let off the gas I would say u-joints. Jack the back end up and have a helper rock a wheel back and forth while you are watching the u-joints for play or binding.

Another thing it could be is the trany, my older 86 did that in OD but not Drive.. If I grove it around in drive for a while it stopped.

 

[Holy Smoke]

My truck is doing some of that now,, I found out that compression was low in two cylinders. I have pulsing out the tail pipe.... (of the truck)

 

[Pete95Sierra]

its gotta be ball joints... replace em and you should be fine... my parents 96 burban does the same thing... just dont forget to realign the front wheels... chevys are notorious for having a bad front end

 

[black jack]

It could anything from tire out of round , out of balence or from a spark plug even a spark plug wire. I had a cougar long time ago that the plug was bad and it did what you are saying.

 

[choo]

So many different replies on what it could be . I was afraid of that ,at least nothing major . I did the u joints a friend said thats why his 01 Denali XL was doing it . The trucks got 115,000 miles on it a tune up and ball joints would be a good investment . Hope it works , I dont wanna start having to replace big$ parts one after the other and have nothing work.

 

[Holy Smoke]

There are ways to test many of these components. Spark plugs, ball joints, universals. Then you can start at the worst one first.

 

[vncj96]

mine did the same it was the tires not wearing even and one of the balancing weights had fallen off but mine did it at 70mph, rotated the tires and had them rebalanced no more problems

 

[ukrkoz]

go to any major parts store and have them scope your ECM with scanner, it's free. at least, you'll know it's not electrical.
mine does that goofy shake dance on specific stretches of roads i usually drive on, i can almost predict when it'll do it.
somehow no one mentioned trannie. you might have clutches slipping. that'll shake awright, and is accelration relevant, as you apply power to trannie. so clutches slip. hope not, it's major issue. check your fluid, maybe it's toast and time to change. sometimes small things work big miracles.