CRAZY vibrations

Hey guys, i just picked up an EG hatch with a B18B ls swap
and i have a few questions:
one, This thing VIBRATES like no tomorrow, at idle and through a good portion of the RPM range
it appears to have stock mounts,
idles at about 1500rpm cold and 6-700 hot
also the car has a heistation about 3k rpms
runs fine from idle to 3k, and from 4k up to 7k
but hesitates really bad about 2800-4000
previous owner said it sat for a year, could this just be bad fuel?
thanks in advance
and i have a few questions:
one, This thing VIBRATES like no tomorrow, at idle and through a good portion of the RPM range
it appears to have stock mounts,
idles at about 1500rpm cold and 6-700 hot
also the car has a heistation about 3k rpms
runs fine from idle to 3k, and from 4k up to 7k
but hesitates really bad about 2800-4000
previous owner said it sat for a year, could this just be bad fuel?
thanks in advance