I drive a 96 jeep cherokee country 4x4 xj 4.0 automatic. I've had this issue for awhile, where I will turn off the engine, and right before the engine stops spinning, it sounds like really hard piston slap on all 6 cylinders. It was occasional at first, but after hi revving activities, it became more frequent. After taking her out on the hi way it started happening about every time I shut it down. Its loud, my neighbors probably hear it. She studders sometimes after shifting into gear on initial start up but usually runs and drives really well once I get her going.

I've also recently replaced the air idle control valve, throttle position sensor, crankshaft position sensor, new wires, distributor cap / rotor, cleaned up the plugs, fuel filter, air filter, did a valve adjustment, checked the push rods, and did an oil change recently. The clattering at shutdown as been persistent through all of it.

I would love some advice on figuring it out

 

valve adjustment?

 

it had a lot of valve chatter before. I retorqued the piviot nuts in sequence, which seemed to help quite a bit

 

Sound like dieseling or run on. Common on 80s vehicles. So carbon buildup in the cylinders. Try a vapor or sea foam into the throttle body to clean out the carbon .

Ron