I have a 97 Jeep Wrangler TJ with 2.5l 5 speed. When I'm in neutral either slowing down or sitting still my jeep will idle low down to like 400-500 rpm and shudder and then eventually stall. It's fine if I downshift when slowing down but I have to constantly give it some gas while idling. I consider myself moderately knowledgable about engines but I have no idea what is causing this. Any ideas?