Engine upgrade to 1.3 is the real solution to this or an overhaul may work,tuning or plugs change oil change etc won't work.
iam using belta since 2012 had same issue knocking,vibration when we turn AC on,its normal on neutral but vibrates more on drive speically when AC is on and break is applied.
Its been 3years i have upgraded engine to 1.3 never had this issue again,also fuel economy,power and Ac all are alot better now with 1.3.
