GMC Repair: vibration 94 z28 at 1500 to 2000 rpm, vacuum line, autohelp

Question
hello nice to meet you,i have a 94chevz28 cam. with 114,000 mls. that will vibrate your feet on   the floor and arm on the console at 1500 -2000 rpm.i have new uv joints,trans mount,tune-up,motor mnts look good.The engine runs fine,but the vibr. always occurs at 1500-2000 rpm.any help that you would give,i will be very gratefull for thank you for your wisdom. stclairer1c@aol.comm  

Answer
What mechanical work or ANY kind of work has been performed on the vehicle recently ?. As most problems that occur after a recent repair was made can be traced back to the area of where the repair was made as a vacuum line may have been knocked loose or a wire connection came loose, Look around in the area where work was performed.

Can you duplicate the vibration with the brakes applied in drive at the specific RPM'S ?.

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