first and foremost any help im given will be greatly appreciated... i recetly bought a 94 z28 not knowing much of its history ive worked at a family owned junk yard since conception lol so figured for the price as long as nothing drastic it was worth it..... long story short when accelerating but only if u try to punch it , you can feel something hitting the middle counsile . also pretty heavy vibration.. but only when accelerating . figured it was was missing having something to do with it but when in neutral runs smooth.... my first instincts would be the drive shaft but it doesnt vibrate at high rates of speed and when taking off from say 40 to 70 no vibration?? should i change the drive shaft and go from there again hopefully someone has ran in to this problem or any help will be greatly appreciated thanx, vern

 

Check the transmission mount. Sounds like it's broken.

The rear suspsension relies on the torque arm to control the rear end torque. The torque arm is attached to the tailshaft housing of the tranny, and lifts the housing under acceleration. If the trans mount is broken, the trans lifts off the cross-member and hits the floor pan.

Many people opt for an Energy Supsension polyurethane replacement, although they do transmit more noise and vibration than some people can tolerate. They do last a lot longer.

This isn't really an "Advanced Tech" question, and you have this posted already in "Drivetrain", so I'll close it. Please don't post the same question in multiple forums.