hey all,

i just picked up a '91 formula

drives pretty nice but theres a vibration after 60mph, it feels like im running over a bunch of little bumps on the ground

just had the front wheels balanced and the problem is still there.

anyone have any suggestions as to what this might be, or what i can do to diagnose it?

 

Could be driveshaft? Or possibly front end alignment?

 

my moneys on driveshaft

 

Balancing on tires?

 

the driveshaft would cause that after 60?

 

well once it gets to a high enough rpm the minor imbalance would be vibrating more


could just be an improperly balanced tire



basically start with getting your tires checked which is dirt cheap then get alignment done( won't hurt it )

if both those fail its the driveshaft

 

FYI ^

I would check you motor/tranny mounts. Check tires for any slight bumps or imperfections. Vibrations can be many things, harmonic balancer, torgue converter, etc. Start with tires, alignment, steering component checks, bushings, tranny mount, motor mounts, re-torque your mounts if needed, then check u-joints and drive shaft pinion angle.

 

Is there any chance that this could be caused by something like a strut, control arm or ball joint?

 

Could be.....but that would be more of a clunking sound...look into that as well.

 

I had the exact problem on my 82 camaro, and i only had it about 6 months before the engine crapped out on me, so i never really got around to finding the problem. But when i went to pull the engine and tranny (2.8/TH-200), i discovered that I had NO, repeat, NO drivers side tranny mount bushing, so check on that. I hope that was what was wrong with mine. Wish me luck, cause tomorrow, the rebuilt 305 gets primed and started (hopefully) for the first time tomorrow :rockon: if that's my prob, i'll post back tomorrow night

 

Congrats and best of luck!

 

Could be u-joints as well, a truck we had drove great until about 65 then had a vibration in it. Turned out the u-joints were actually loose where they connected to the rear and caused the vibration.

 

Go down the road a littlel faster than when the vibration starts, say 70mph or so. Once cruising put the car in neutral and see if teh vibration goes away.

If yes then teh vibration is engine or torque converter related.


If no than it is tires or driveline related. I had a similar problem with my 89 IROC. the car had been sitting for so long, and teh tires were close to bald that there were small flatspots that caused a nasty shake....


Best of luck...