My manual '99 TJ has 286K miles on the 4.0L. It began rattling a few months ago and now it's louder. I took it to a mechanic who said it could be a wrist pin and a friend says it could be a piston skirt. Either way, it sounds like I need an engine. The mechanic was able to find a 4.0L with 115K for $1300 or a new/rebuilt for $2500 from Napa. Does anyone have anything better or any suggestions?