Hey everyone,
99 4 runner v6 4wd with a strange issue.
On the highway at 50+ mph, my runner starts to cavitate left to right swinging wildly until i sharply turn the steering wheel to break the growing motion.
Its as if people were lifting the front left fender....then the right.....then the left causing a left to right cavitation.
like i have no swaybars . any ideas?
i checked the swaybar links, wheels and front end.
tires are fine.
No glaring issues . It does not happen all the time. Thx!

 

Suspension related. Check everything including the panhard bar in the rear.

 

I would be checking everything suspension related aswell including shock mounts, rear sway bar, broken frame, broken trailing arms or pan hard bar or mounts, loose wheels, bent rims, dragging brakes/warped rotors, body mounts..

 

Mine did that a year ago or so. I checked everything carefully, all the bushings seemed snug as can be front and rear. Eventually just had someone shove the car sideways back and forth (shoving on the rear bumper) so the truck wiggled back and forth, and noticed that the panhard rod had about 1/4 inch of play on the axle end (which didn't seem to show up when wiggling the bar or even prying at it with a big screwdriver). Replaced the bushings on both ends, and the wiggle was gone.

Symptoms sounds pretty much exactly like mine. Nothing unless I was traveling at highway speeds, and then, usually instigated by a road heave or something, it would start a back and forth wiggle. Fairly slow cycle, never go too out of control feeling. But I did figure out to steer it in a bit of an arc to break the cycle (vs. the instinctive countersteer I kept wanting to do).

I was pretty surprised at how such a small amount of movement on one end of the panhard rod lead to so much wiggling and waggling on the highway.

 

Thx! Your description is dead on to my situation down to the last detail.
i'll be under there today tightening things up !!

 

Took a quick dive back under there and the panhard bar seems pretty snug with no movement.
but......one of the upper dogbone links bushings is broken bad in a few places as well as a bushing in the lower control bar link.
Just ordered replacement parts.....

 

Upper rear control arm bushings are captive, I believe the lower rear control arm bushings to be pressed in and replaceable in the 99 (early 3rd gen lowers are captive).
However: have seen replacement poly bushings available for both upper and lower.

 

Thanks, just received an upper arm and lower arm.
100 bucks shipped .. ordered friday....here on tuesday.
crazy....the vehicle acts as if it wants to steer from the rear wheels!! I'll install them tomorrow morning .

 

Wow...those bushings were toast!! They were moving like
heim joints!!
No wonder it felt as if the runner was steering from the rear!
thx for the help!