[86StangLX]

Hey Guys! I know there was just recently a post about weird vibrations a few days ago, but my problem is slightly different, and very odd. Here's my problem: My car is vibrating from 30-35mph, no matter the RPM. It doesn't matter if I stomp on the gas, or just slowly accelerate, it vibrates from the steering wheel and the floor from 30-35mph. It doesn't vibrate at any other speeds. I really can't figure it out! Any help would be awesome!
-PAUL

[Vortex]

most common probs are
driveshaft not balanced, wheel or tire not up to par, bad springs/shocks. etc.
have you tried having the wheels rebalanced? this usually # 1..
has the vehicle ever been wrecked? hit any large potholes?

[86StangLX]

Vortex, thanks for your quick response! Wheels and tires are fine, only a year old. Might look into having the wheels rebalanced. The vehicle has never been wrecked. And, no, I don't recall hitting any major pot holes. I'm really at a loss. Wouldn't it be giving me problems at all speeds if something was really wrong? Isn't it odd that it only does it from 30-35mph? I'll starting looking into some of those things. You got anything else? Any more would be great. Definitely a difficult problem to narrow down and diagnose! -Paul

[Vortex]

yes, over the computer its quite difficult... but if thats the only symptoms then either way it should be tough.... are you making the kind of horsepower to rip a motor mount? not saying thats it, cuz that would be all the time mostly... if its the specific speed and not rpms then i would rule out engine. but like i said, could be driveshaft, suspension, bent axle(s), differential... but feeling it thru the steering wheel i would have to say front end. possibly tie rod end, ball joints, wheel bearings, pitman arm, all the stuff that goes out over time... has it all been properly lubed at oil changes?

[ScottHalliday]

Paul, did you find the cause of your vibration problem?

[Twister]

check the driveshaft bolts, they might be loose

[GT Dan]

It sounds like a "dynamic" out of balance wheel problem. In the old, old days....they had bubble balancers to balance tires (I'm really dating myself now) and typically one could not determine from the machine how much weight to put on the inside and outside of the tire. In the 70's, they came out with dynamic wheel balancers (now they are all dynamic). Back to my point, the tire could be in balance with the bubble balancer but not have the weight properly distributed inside and outside (sometimes its all on the inside or all on the outside...just depends on the weight of the rubber and the rim of the tire).

You may have thrown a weight or your tires may have not worn properly.

The exact problem that you described use to happen even when the tires were balanced with the bubble balancer, but not in balance dynamically. That is why engine RPM is not a factor.

On small mustang tires this can be easily fixed. On large truck tires or 4WD's, sometimes a tire needs to be trimmed a little because just too much weight has to be used to correct the problem.

You should get your tires balanced regularly (6 month min) and monitor the tire pressure about every other tank fill up. And always watch your tire pressure when the tempurature changes dramatically or before taking along trip. If you watch and take care of your tires they will perform at their maximum capacity and wear as long as possible.