Our crap heap of a 1.2 engined, 14 plate did the exact same thing in vibrating at around 3,000 rpm and destroying those rubber bushes, this also coincided with an exhaust note change and was getting worse, even the independent engineer we got to test drive the car noted it. I still can't believe there wasn't supposed to be anything wrong with it and am glad we got shot of it. The other day gave our old 09 plate Panda a quick look at before its next service is due next month. What a difference! The engine is smooth and lively, in that you don't feel you are pushing it all the while, where the other felt like it was going uphill all the time.