Hey dan... take the rocker cover off and check the chain tension... they can stretch apparently. Timing chain rattle is alot different to lifter tap. The only way u can 'tune' a car is to get the fuel & ign map changed on yer ECU..
EB1 3.9L MPI Falcon Wagon with converted T5 / Pacemaker & 2.5" Redback sports exhaust / 2" lowered blocks at the rear, Kings lows up front / ED Tickford Head and Cam / K&N panel filter with XH intake Snorkel / Full EL Fairmont interior with woodgrain
89 EA1 3.9L TBI Falcon Sedan with 3 speed auto / currently being upgraded...