Vibration over 70mph, only when on accelerator

[krisp]

Hello,

I noticed last summer that my 2005 Explorer would vibrate when the cruise control was on and I was going down hill, at low RPMs but on the gas. Well, the cruise control doesn't even work anymore but that's a different problem. Anyway, I noticed yesterday that in a straight line on the highway, if I'm on the gas over about 70mph, there is a lot of low frequency vibration, and if I let up on the gas it goes away. It's very apparent and seems to be a new problem.

Any ideas?

 

[Jakee]

When you're on the gas there's load on the drive shaft. When off the gas the drive shaft is not loaded. So it seems the u-joints may be the problem; look there first.

 

[krisp]

ok ill have it looked at thanks

 

[Sams01XplrSprt]

maybe u need an alignment