It is probably the bushing that is in the pyramid shaped metal bolted to the front floor pan. There is also a bushing in the control arm toward the motor. You might as well get a kit from ipd and replace all on both sides. If you've got 120k miles then you might look at the outer tie rod ends and ball joints. If the boots are split then the grease is probably gone. These are permenently greased. You don't want to loose a ball joint at speed cause the wheel will come loose and make for dangerous poop in the pants driving. You also could have a broken stut tower mount which will also cause clunking.
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92 244 lowered, Bilsteins, IPD sways, Unitek cam/header, TSW Revo 18x8's - 94 965 Niiice MONEY PIT! - 76 Datsun 280Z lowered, modified head, cam, headers, intake