Could be that your valves are out of adjustment or if you have the nonadjustable valves then it could be a build up of carbon on the valves.
And engine knock is normally caused but I worn crankshaft bearing or rod bearing.
Sometimes the Timing belt tensioner will cause a tap or click until the engine is warm.
bad bain bering
Engine knock happens when an unbalanced air and fuel combination occurs inside of an engine cylinder. If the problem is not corrected the vehicle runs the risk of having a piston malfunction.
The lack of oil?!?
Low octane fuel, timing to far advanced, overheating.
Not enough oil or a spanner in the works.
The knock sensor just advances and retards the engine timing only. If there is a noise in the engine then you have engine are valve train problems. The knock sensor will not make the engine knock.
Cold engine knock that goes away after warmup is usually piston slap. Worn pistons worn cylinder bores, wrong oil (too light) on a high mileage engine.
This is controlled by a knock sensor.
If it's a engine knock it could be low on coolant or have head damage...
I have a recent engine knock on my 91 escort started out intermittant. I have a recent engine knock on my 91 escort started out intermittant.