I had a 97 rebuilt 4.0 put in my 2000 xj and I think it's knocking. It does it every time I give it a lot of gas from an idle and occasionally it will miss and do it. I think it's rod knock but it disappears when the rpm goes up any clues? Should I drop the pan and take a look and see if I can wiggle some bearings?

 

I'd look at the flexplate bolts first.

 

^ This, a loose/cracked flex-plate on a 4.0L I6 can sound almost exactly like a rod knock.

 

Will do tomorrow and report back

 

I'm sure it's already been said on this forum before but what is the flex plate? Where is it? What does it do? Is it hard to get to? I hear a small knocking from my engine at idle and would like to check out the flex plate. Thanks guys

 

Here- with pics:
https://www.cherokeeforum.com/f51/ho...ocking-125547/

 

And a crack check here> https://www.cherokeeforum.com/f2/fou...emoval-171945/