if the vibrations were only at idle it'd just be the mounts doin their thing, but it sounds like you got bigger problems.
How To: check your codes:
Under the hood theres a yellow rubber clip on the Driverside shocktower, take off the rubber cover, and insert a wire or paperclip into both sides after starting the car.
If they used a wire harness like a Rywire one, their may be wires for you to cross coming off your ecu harness.
Anyway, this'll make your ecu blink out the code, and if your obd1, the check engine light will blink it out.
1 long blink = 10
1 short = 1
long pause = break inbetween codes
count the blinks and add it up, ta da.
you can get more info on code checkin on rywire.com or ht or alot of other sites, id be more thorough but its dinner time
