my 68 coupe keeps vibrating off and on while im driving it has a v8, auto., and p/s any ideas???? i cant figure it out thank you

 

when does this problem occur? is your car vibrating when you slow down from high speeds? (ie 70-0) could be a brake problem

 

It could be a lot of things, just start eliminating possibilities. Check the ball joints and tie rods for looseness. That would be where I would start. Also, check the sway bars...had one snap on my Taurus and it vibrated off and on. Check your tire tread for any irregular wear... your car may need an alignment. If you take it in for an alignment have them check the tire balance as well.

 

first, do you feel it in your *** or hands? turning in particular direction, rpm, speed, accelerating, decelerating? i know im being short but that's the core of what we need to determine the problem. Also, have you done any modifications lately and it started after that or has it always been present?

good luck

 

id start by rotating the tires if the noise moves to the back its the tires if its still there could be alot of things bad motor mounts tranny mount unblanced driveshaft wheel bearing ball joint

 

Just remember that it's an old car. At idle, my door rattles on the inside and each lock vibrates as well (annoying since it's not actually broken. Old cars vibrate a lot.

 

U-joint in the driveshaft going? Does the vibration happen when you get on or off the gas?

 

its happening while im driving and when i slow down and it goes through the whole car the only thing thats modified on the car is the motor and it not the typical motor vibration it does that to, this is whole different type. i thought maybe it the suspension be im feeling going under me to the back of the car. i replaced the sway bar bushings and the sway bar looked fine small butt fine. i would like to go through and replace everything because my pregnant wife and two kids ride with me alot but i dont have the money to do that know i would like to try and pin point it to one area i thank you guys alot for any info you give me

 

Check your universal joints ,sounds like they may be worn out.Thats a fix right now kinda thing.If they are bad dont drive it
Jeff

 

Along with the various other bits of advice people have given, check to make sure your exhaust is not touching anything it shouldn't be touching.

My car has always rattled, but when the exhaust hanger on the passenger side got bent and just barely pushed the exhaust tip next to the back bolt holding up the leaf spring, it caused various parts of the car to rattle at different RPMs. I couldn't trace it entirely, so I started stuffing rags in various places because the sound was deafening at idle. Then one day while washing the car, I saw the wear spot on the exhaust tip, got a crow bar and bent the exhaust over about 1/4" and the car was back to her old, much quieter rattles.