Any other tips??(motor mounts)

I own a 91 XJ limited, had my engine rebuilt about 7-8 months ago(16,000) when they did the engine I had them do everything including the motor mounts. Well now when I acclerate fast I feel a hard/loud clunking under my feet, and as long as I keep the throttle down nothing happens, but as soon as I let off the gas from acclerating hard it clunks back. I have now confirmed with 2 shops the left motor mount is bad, would that be causing the clunk when acclerating and the clank whenI let off the gas??the rubber being bad on the motor mount?Any suggestions would be great!!Hard to change the motor mount on the driverside???Thanks!!

You need to replace the motor mount anyway. Do it and see if your problem is solved. It isn't that difficult. Pull out the air filter box so you can get to it.