changed all mounts car vibrating still..help please
 

hey guys i just got a 97 mazda 626 i4 the car started shaking when i stopped at a light and the rpm's drop to about 700-750. when i am driving the car is fine no vibrations only when i slow down or stop and idle, i had all the mounts on the car replaced, i think there is 4 but i still have this bad vibration. i have no loeaks anywhere and change plugs and wires. is there a certain way the mounts had to be installed? i had the mounts rechecked but the mechanic said the are not broken, please help with this mystery.....