Iv'e been having this problem in with my truck for the past probably 3 years. I've been trying to narrow it down to specific situations for a long time, but can't come up with any ways to replicate it every time. My trucks specs are: 2002 XLT 2WD, coil spring, stock tire size.

Basically my whole truck shakes about 5 times a second just enough to feel it sitting in the seat and on the steering wheel when I'm driving. It is almost always present and the roughest when I brake, although lately I have been noticing at certain times when I let off the gas and sometimes I think I can feel it when I'm just cruising. My first and obvious suspicion was warped rotors. I had those replaced about 2 years ago and the problem lessened for about a week after then went back to normal. About 6 months ago I had all of the shocks replaced, ball joints, upper control arms, and tie rod ends all replaced as well. This didn't help the pulsing much at all.

Any ideas on what could be up?

 

How old are your tires? do you rotate them regularly? have they ever been changed?

 

Tires are about 2 years old. Haven't been rotated as much as they should, but they've definitely been changed since this started occurring. I will rotate them this coming weekend just to be safe though.

 

sounds like off balance tires.

 

Perhaps I have been 'rotating' my tires incorrectly. What is the standard position you switch them between when properly rotating? Such as front left to rear right or something.

 

it doesnt matter too much what way u rotate them as much as regular rotation. you can do an x pattern or side to side. I think the above poster was suggesting your wheels need ot go to a shop to be rebalanced.

 

Correct, it sounds like the tire's are off balance, the way you rotate does not matter, i've had some people do them both ways and it doesn't matter.

 

I have a similar problem. My wheels/tires are "balanced", about as good as you can get with steel rims and 35s, and still have that shake while decelerating.

I've changed a wore out front driveshaft, didn't help. Next is going to be u joints and grease the slip yoke in the rear driveshaft. Not sure if yours has that.

 

Bent rims can still balance perfectly. Have your rims checked for straightness too, not just balance.
My truck recently got all new ball joints and still had a little wiggle to it. Replaced all the rubber bushings on the arms and the front wheel bearings. Problem solved. She rides nice and smooth now and corners a heck of a lot better too.
02 thunderbolt (XLT) 3.0