is there an adjustment for valve lash. on 1996 Pontiac Firebird

I have a 1996 Firebird with 3800 SeriesII, no add ons. I have an extreme chatter, almost a rattle/ticking under the left bank valve cover. I've tried the oil additives to avoid opening up the top end.No help. Any advise?

Asked by for the 1996 Pontiac Firebird
poss worn out rocker arm, pull valve covers and insp all rockers and oil to top end of motor
Greg is correct...pull valve cover and inspect rockers for loosness...I have seen valve tappets fail also...
Thank you.
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This engine is equipped with hydraulic valve lifters, there is no provision for adjustment.
Thank you for the response. Is there anything specific to check? Valve spring, seat, rod or lifter?