My '96 xj has developed a new noise within the last two weeks. It's a somewhat loud/annoying noise seeming to be coming from the motor. My oil pressure hasn't been affected nor has the motors performance which leads me away from it being a rod knock. So I pulled the valve cover and all of the lifters seem to be functioning. Just looking for other ideas of things to check.

 

cracked header ? is it worse when you apply throttle ?

 

My exhaust manifold is cracked but has been cracked for some time now. It's a little louder when accelerating and more repetitive