Jitters on bumps

1985taylor1925

1985taylor1925

Senior Member
Just bought a 1998 4runner SR5 less than 2 months ago. I love the vehicle, and I think Im sold on it for life. But it does have a case of the jitters. I just replaced the original shocks (they were original with 160k miles!) with KYB gas shocks, thinking it would fix the problem. But the vehicle still feels jittery over a lot of bumps. Im thinking of replacing the bushings in the sway bars as my next step. The jitters feel like they are coming more so from the back. Its a similar feeling to driving over water washout rivets on a dirt road. But im driving it on normal, paved roads. And it actually feels worse on little bumps than it does on bigger bumps. It doesnt have any body roll, so I really dont what it could be. Can anyone give me a diagnosis on this issue? Thanks
 
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Used to drive a ford taurus. but the jitters arent normal. its not just a stiff ride. iv driven my dads tundra and ford f250, and brothers dodge ram, and also test drove a few 4runners before buying this one. those are all stiff riding vehicles, but none had this type of issue
 
What psi are you running in the tires, and i doubt it is anything to do with the sway bars. I dont have the sway bars on my 4runner it is smooth on everything. I live on a dirt road and even the washboard is smooth
 
Im running the recommended - 44psi in all 4 tires. The two front tires are brand new goodyear wranglers. The rear have plenty of tread. All though they are cheaper tires. But i dont think that could be the problem. why did you take off your sway bars?
 
1985taylor1925 said:
Im running the recommended - 44psi in all 4 tires. The two front tires are brand new goodyear wranglers. The rear have plenty of tread. All though they are cheaper tires. But i dont think that could be the problem. why did you take off your sway bars?
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I run ~36 psi in my tires, try this.

Is it lifted of does it have the stock springs? Is the back sitting on or close to the rubber jounce bumpers (the rubber cones inside the rear coils) These are for carrying heavy loads but the stock springs sag and will settle to the bumpers.
 
No lift. They are the original springs. But the clearence is good. No sag in the front or rear. There is plenty of space between the rear axel and the rubber stops above it. Honestly the ride feels very good as far as stiffness and overall handling with the new shocks . . . apart from the jitters. Even my buddies noticed the jitters driving around last night. It doesnt bounce back and forth or side to side. Just feels like the vehicle is being shaken . . . like its having a mini seziure. I'll decrease the tire pressure a little and see what that does. What about the bushings on the swing arms in the back (not sure what they are called)? Or the control arms or a-arms up front?
 
Any clunking sounds? Does everything underneath look right? Wheels loose? shake the rear end (hard, side to side) any clunks? Do the same to the front. Have you gotten an alignment? Steering rack bushings? And type of wandery steering, clunks in the steering?

Have some one shake the rear end, do all the links look tight? Take a pic of the rear springs, and the cones.
 
1985taylor1925 said:
Does anyone else have any idea what might be causing my 4runner to feel so jittery on bumps? thanks
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I would look into replacing the stock steering rack bushings with the energy suspension poly set, it made a huge difference to the way my runner felt going over bumps and the steering wheel feel. The suspension also should be inspected for worn components.
 
1985taylor1925 said:
No theyre rt/s
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i had the goodyear wrangler rt/s before my cooper discoverer st's. and vibrations plagued me till the day i got the coopers. maybe it was me being a perfectionist OCD freak. i dont know, i do know that it completely stopped after getting rid of those tires. one spec of dirt and the balance seemed to be thrown off drastically no matter how well u washed em.... good luck.

BUT....if you got serious jitters, i would def replace all of your shocks. if they are original, you need to replace them. drivin around without having your tires balanced properly will also wear out your shocks much quicker than usual. i just know that when i put new shocks on mine, i went downtown (charleston, sc) to see what the difference was (for anyone who has been downtown charleston they know how bad the roads are.....). the difference was SOOOOO amazing i think my girlfriend wanted to slap me everytime she was in the car with me cause i would shut my mouth about how much better it rode. I mean, seriously, it was so much better. and it didnt feel like my freakin tires were bouncing off the ground every time i hit a bump. u could tell that the shocks where holdin those tires on the ground... again, good luck with solving the mystery.

AND ONE MORE THING.....i used to keep the "recommended" pressure that was listed on the tire. ill throw a negative on that decision. rode like crap. felt every pebble i ran over, and just was flat out rough ride. thing was pretty squirrely to drive too with all the pressure in those tires.
 
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for all the recommendations, thanks. but i just put brand new kyb shocks on it, and the jitters are the same. I also just got the wheels balanced on a gs9700 machine i think its called, which is supposed to do a perfect balance. lug centric rather than hub centric. springs are good. everything else looks good. it was just aligned and they said all front end components looked good.0 lug nuts are tight (i check them myself after getting it back from any shop). there is no play in the steering, although the bushings may be something to look into. i also brought the pressure from max 44psi down to about 40. still have the same jittery feeling over a lot of bumps. like the vehicle wants to jump around. im thinking of buying new sway bar bushings. is that a good idea? or what about removing them entirely to see if they are the cause? any other ideas what might be wrong, with the above in mind?
 
1985taylor1925 said:
for all the recommendations, thanks. but i just put brand new kyb shocks on it, and the jitters are the same. I also just got the wheels balanced on a gs9700 machine i think its called, which is supposed to do a perfect balance. lug centric rather than hub centric. springs are good. everything else looks good. it was just aligned and they said all front end components looked good.0 lug nuts are tight (i check them myself after getting it back from any shop). there is no play in the steering, although the bushings may be something to look into. i also brought the pressure from max 44psi down to about 40. still have the same jittery feeling over a lot of bumps. like the vehicle wants to jump around. im thinking of buying new sway bar bushings. is that a good idea? or what about removing them entirely to see if they are the cause? any other ideas what might be wrong, with the above in mind?
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Before throwing any more money at this problem, is there any way you could drive another 4runner similiar to yours and see how it drives and feels?
 
Poly steering rack bushings, they are a pittance compaired to the other parts you have bought, I don't think you will be disappointed, I certainly wasn't.
 
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