Try checking your engine mounts and bolts. On my Engine was it a misfire condition,the sparkplugwire from cyl #6 came loose I have a 96 Camaro RS 3.8 L.The other time it was a small Vac Line by the Throttle body,that caused a bad shake
The fact that it's a piece of junk chevy, get a mustang. Ford all day.
if this happens at a certain speed it's probably the alignment of the tires.
Could be a broken motor mount.
Check the motor mounts.
The lack of oil?!?
YES it can, but the engine would vibrate and shake if it did.
Can be engine miss or broken motor mount.
Misfire, bad spark timing, bad engine mountings.
Cylinder misfire. Possibly failed or failing engine mounts.
bad/partially blocked catalytic converter. - kind of a rotton egg smell, right?
Does it do it when you take it up to about 50 to 60 and then let off. If so then it could be your u-joints on your drive shaft.
Here are some possible causes: 1. Warped flywheel. 2. Engine out of time. 3. Engine misfiring.