Celica Forums General Discussion Engine and Performance Suspect timing chain knocking

Went through a process of replacing lift bolts, cleaning out OCV filters, and replacing an oil pressure switch, with an oil change of mobil 5w30 to get lift back and working recently on my gen 7 T-Sport, which it did, after 3 or 4 times engaging lift a pretty loud and rpm matching knock started coming from the engine and the throttle pedal felt kind of like it was struggling. Took the valve cover off to take a look and nothing was visibly wrong, but the timing chain did have some slack in it, put it back together to listen to the location of the knocking and it sounds essentially like the chain is slapping the underside of the valve cover. The engine is on about 96,000 miles

Was wondering if anyone has had a similar experience and any advice, could it be that the tensioner just needs replacing?

The noise: Engine sound [streamable.com]

Any knocking, rattling noise from the engine can mean serious problem. Does the knock sound faster at higher RPM?

It sounds like the timing chain is knocking on something in the valve head area. You may want to open up the valve cover and look for any loose items near the timing chain. Possible parts of the broken lift bold may have rolled into the chain.

Be very careful with the timing chain. If it's jump teeth, it may break your cam shafts and valves.

But if it's loose, you may want to remove and inspect the timing chain tensioner on the engine block passenger side. It has a spring-loaded plunger that presses against the plastic chain guide to keep the chain tight. If it's weak, the chain will be loose.