Bad vibration
 

Have a 94 f150 with a 351w swap.. Just a couple day ago my truck developed a bad vibration that is worse just above idle then anything else.. I replaced both motor mounts one of which was broken but it did not solve the problem. Changed plugs as well and still have the issue.. The balancer seems ok to me took belt off and there isn't any play in it.. Not sure what else to look for.. It does it in park when I rev it up so I figured that eliminates it being anything to so with the drivetrain

Is it running on all 8 ...
Torque converter/flywheel loose ...

-Enjoy
fh : )_~

Yea running on all 8.. It smooths out once I start driving and get the rpms up but it has the vibration at low rpms jus above idle