Hello everyone! I was hoping I could get some help with identifying this noise in the engine bay. I am going to link my post in the XJ reddit that outlines the problem, and includes a video with the noise.

https://www.reddit.com/r/CherokeeXJ/...ise_rod_knock/

As I say in that post, you can hear it about 4 seconds in for a hot second, and when I apply throttle to it. It doesn't sound like typical rod knock, or really any noises that I've heard. I have recently put seafoam in the oil before I do an oil change, and I will say the noise has actually been happening even more now. It still isn't loud enough for me to notice, but it does continue to happen even after driving it for a bit. Could this be piston slap, or even just a timing chain? Still no loss in power or oil consumption, and oil pressure is still normal, but it would be nice to finally put this noise to rest.

 

What year is it? I know the earlier 4.0’s had piston slap on cold start, or at least i’m pretty sure. That’s what it sounds like to me

 

It's a 91. Also is a stick so it can't be the flexplate that always gets brought up.

 

Went out and did some more testing today, as well as got some more footage. Went around and unplugged a spark plug one at a time. Noise still as apparent as always. And then I took this video. Also decided to ask the reddit as well.

https://www.reddit.com/r/CherokeeXJ/...oise_any_help/

You cant hear it as well in the beginning, but when I put my phone under the dash you can distinctly hear it. Do this help diagnose the issue any more? I have a boroscope coming in today, and plan to drop the pan on Friday, but would like to avoid that if at all possible.