hi, whenever i take my foot right off the accelerator when its in gear, the car jurks as if i'd jabbed the brake slightly, but it doesnt do it when the clutch is in. also sometimes when i do it, it feels like the engine and gearbox are juddering for about 5 secs (sort of like kangarooing). any ideas what the problem might be, ive heard the gearbox mounts are notoriously weak.