I've tried searching a thousand times and can't find this combination of problems. I've been driving my wifes 98 cherokee classic automatic 4.0 with 92,000 miles for a while now. Well for about a year now its been having this popping rattle sound. Within the last 2 weeks It still rattles but when I start the jeep or turn it off it sounds like my diesel pickup truck, a few loud rattles (maybe 3 or 4) . I've tried troubleshooting the problems I searched on here for, First the Cat. well that wasn't it, it was quiet and the sound was coming further towards the front. I thought about the flex plate, but I saw on here that if it was that then It would still rattle at all rpms where mine only rattles at below 1000. This rattle is at Idle in all gears and gets 3x louder whenever I cut the A/C on.
so heres my questions
1. If it were the flex plate would it rattle at only 1000 rpm or at all rpms?
2. would the A/C affect the rattle from the flex plate
3. If it is a fan shround would it stop after 1000rpm?
4. If it were a slung rod wouldn't I be down a cylinder and wouldn't i notice a problem with performance, how do I check?

also the rattle sound is random, like its been said on here as marbles in a coffee can. any help is appreciated since I'm driving around in 103 degree heat worried to cut the a/c on thinking I might break something
Thanks

 

Never mind I just found out from somebody else on here how to figure it out. I took a metal pipe, put it to my ear, then the bottom of the motor, no sound. Took the pipe and put it to the transmission..tada rattle. I guess the flex plate will only rattle at low rpms on some occasions. Thought that was a neat trick though, I'd always heard of using a hose but never thought of a metal pipe