Toyota Repair: 91 Celica GTS Vibration, toyota celica gts, service receipts

Question
I just bought a 91 Toyota Celica GTS that is in great shape. It has only 79,000 miles on it and runs pretty good for the most part. I bought it from an older gentleman who had all the service receipts on it showing that he had replaced everything according to the owners manual schedule. He even had all the service done at the toyota dealership. The only problem I have with it is that is vibrates pretty bad when it idles at 1100 to 1200 rpms. the normal idle for it is around 800 rpms after it is warmed up. So when I am driving and coming to a stop and the engine is slowing down to 1100 to 1200 rpms it gets a bad vibration in it that shakes the whole car pretty bad. I am thinking motor mount. What do you think?  

Answer
Yes, the motor mounts need to be checked, a common cause for this is that the car has been in an accident and one or more of the mounts doesn't fit correctly and is making metal to metal contact with a crossmember, concentrate on the crossmember and the motor mounts and you will probably find the problem.