4.0 Knocking/rattling noise from engine.
Hey everyone I'm new to this forum. I recently purchased a cheap WJ as a project with 286k miles on a 4.0 for $600 I was expecting to do some work on it. Anyways it was running like crap and had a ton of codes it also was throwing a crank sensor code and upon inspection I noticed the crank sensor was loose. I tightened it up, gave it a tune up and the issues went away but ever since there has been a slight knocking sound at idle. I cannot figure out where it's coming from.
On a cold start it's a rattle type sound then a few seconds later once the idle drops it turns into a knock/tap . If I rev the engine it quiets down to almost silent but you can hear it getting faster with the rpms. Oil pressure seems fine at 40psi and goes up a little when driving. I'm clueless as to what it can be . Possible timing chain? Bearings?