clunk when pressing gas pedal

[TopGun007LTK]

SO here's my deal. accelerating from a dead stop produces no clunk. but say I take my foot off the gas....then reapply....I'm met with a clunk when I hit the gas pedal. It also seems to be almost rocking back and forth as it goes. A very strange sensation. Like a shaking back and forth feeling as it goes. This Clunk is much worse at high speeds.....if I am going over 70mph, and I take my foot off the gas pedal, it has a violent clunk followed by an instantaneous 4mph drop on the speedometer...then another clunk when applying the gas again.

Necessary info: The truck has had an alignment recently, new tires and I don't think it's a wheel bearing issue.

 

[Damo]

I've had trouble ever since my tyres were changed, and I am advised that this is common with Explorers. I'm going to have the wheels rotated and balanced to see if that helps (though it may make it worse, of course)

 

[Glacier991]

Try this, put it in reverse move it, shift it into drive and see if you hear any clunk. Try that with varying degrees of drive acceleration too. You may just be unloading a U joint when you take your foot off the gas and then the sudden loading when you reapply the gas may produce a clunk. That or a slip yoke lubrication issue.

 

[TopGun007LTK]

There is a definite clunk when shifting into R. not a clunk when shifting from R to D, at least not after it's warmed up anyways. The whole truck seems to run smoother when it's wet out. I don't know what that means. Right now it's snowing out and the truck seems less jittery. The clunk upon applying the gas pedal while driving happens intermittently. It's not a constant, except at higher speeds, mostly around 63+, maybe it could be the Torsion bars as well as something else?

 

[DBray6]

I have this same problem in my 03 Sport Trac. I am planning on looking at it this weekend. Did you ever get this solved?

 

[DBray6]

I have this same problem in my 03 Sport Trac. I do not have 4WD. I am planning on looking at it this weekend. Did you ever get this solved?

 

[jorlain]

My guess would be a motor (and/or transmission) mount or a u-joint.