My friend has an 86 and it vibrates the whole car pretty bad between 3 and 4 k rpms. Is this from the u joint in the drive shaft or what could it be? Any ideas would be greatly appreciated

 

Up to this point its not been that irritating but now that he's getting ready to mod i think this is something that should be addressed first. Btw he recently had his clutch replaced. He's either going to get a driveshaft or the corksport exhaust. thanks

 

Does it vibrate 3/4000 in each gear or only in 4th,5th?
Vibrate when engine speed increased to 3/4000 in neutral?
You can do a search on driveshaft vibration in 2nd generation.....Lots of information

 

If it turns out to be the ujoint, i got a driveshaft that has a new ujoint for sale

 

Is the vibe RPM dependant or speed dependant?

If it is speed dependant, then it's probably the driveshaft.

If it's RPM dependant, it's something else.

 

I tend to think its more speed dependant. At about 40 or 50 mph.