What could cause the engine to shake in a 1993 Toyota Camry if you already replace both motor mounts?

Does one of the replaced motor mounts include the transmission mount which could actually function like a 3rd motor mount? Check that as I have seen them go bad.

Answer

Spark knock can cause engine to shake get your car checked for emissions

Answer

93 4 cyls are notoriously "shaky" if you feel it mostly in the steering wheel and its not too severe, there is a TSB from Toyota that has a number of parts in it that may help. improved (softer) radiator hoses, radiator lower mounts, as well as the motor mounts you've already replaced are included and have helped me to fix many similar problems.(a tuneup can help this also and its really the best place to start). the car is no longer under warranty however so you will have to pay for the parts and labor to fix it.