Hi, i've got a 1993 sc300 5speed all stock. It has a vibration when i rev the engine in neutral. I looked at the motor mounts and it looks new. The rubber in the tranny mount does not seem to be torn. It sounds like i have a slight exhaust manifold gasket leak but i don't think that would cause it. The car drives great except for the vibration. I did search but could not find anything similar. thanks

 

Flex coupler on the driveshaft perhaps?

 

would the flex coupler cause it to vibrate while not on load? i'll ck it out though thanks