I was accelerating, at about 3000 rpm I lost all power and the rpms dropped, I also heard a knocking, all while I was still giving it throttle. As soon as I let off the throttle everything went back to normal. I hit it again and the same problem occurred. I noticed that it happens only in 3rd gear. This is the first time I've had this happen. Any ideas on what it was? It's a 2000 xj with 180000.

 

Sounds like 3rd gear took a dump. And you are positive this only happens in 3rd? Everything sounds/feels good in neutral or 1-2 gear?

 

Well I drove it home after it happened and as long as I kept the rpms low it was fine, I think it was just a coincidence that it happened in 3rd.

 

So you can't rev past 3000 without losing power and knocking noise? Even in Neutral?