Check your serpentine belt (or belts if SCV6) idler pulleys, there are three on the primary belt (one on tensioner and two on the top between alternator and water pump) and they rattle making "diesel like" noises when worn that many confuse with timing chain noises. Takes ~5min to check (just remove the belt and check pulleys for rattle). Tensioner pulleys can be replaced without needing to replace the whole tensioner and are ~$20 each (primary - LR035546, pulley only - Febest 2987-DIV; supercharger - LR039517, pulley only - Febest 2987-RRS), and main idler pulleys are ~$60 (primary - LR106769, LR039516, supercharger - LR035545). Everything take less than an hour to replace.I just had a timing chain done by my friend. New tensioners, chain, water pump, injectors, spark plugs, radiator, and starter. It still seems loud, like the chain is slapping. I know he put the new guides on. Any ideas?
Also supercharger worn coupler makes similar noises, easy to rule out by removing supercharger belt. Coupler is ~$20-80, and I'd replace SC oil too which is ~$20-40