The engine moves back under hard acceleration and sounds like something is rubbing somewhere when it happens then.
I'd check the engine mounts for play, and check the top engine mount cup isn't broken. Assuming they're all alright, check the exhaust isn't rubbing anywhere, then just generally check everything around the engine/bulkhead for signs of rubbing. Its a bit of a pain that you cant just get out an check with a fault like that lol.
As for not slamming them, your sig shows otherwise.
Edit - Btw, it hasn't got an undertray hanging off has it? Don't overlook the obvious.
I'd check the engine mounts for play, and check the top engine mount cup isn't broken. Assuming they're all alright, check the exhaust isn't rubbing anywhere, then just generally check everything around the engine/bulkhead for signs of rubbing. Its a bit of a pain that you cant just get out an check with a fault like that lol.
As for not slamming them, your sig shows otherwise.
Edit - Btw, it hasn't got an undertray hanging off has it? Don't overlook the obvious.