haii...can anyone help me with this..

i bought 2nd hand wira last 2 weeks..it seems nice..but only 1 problem,
if i drive with passengers, mmm bout 3 people in the car, the exzos make a loud noise if i langgar lubang..not only lubang but if jalan bukit2 also..i mean jalan x rata la...i thought the exzos kena body or tayar..then i went to exzos shop..he said nothing wrong with the ekzos..anyone got idea???is it about the absorber??