Savage 4.6 loss of power/rpm why?
 

When I drive on thin dead and grass and gravel once my engine (F4.6) reaches a certain RPM it stops there, and sometimes I think it slows down. I thought it was my stock shoes, changed them, but its still happening.

My slipper is tight, gears are meshed fine, tranny is fine. Anyone have any ideas, or has happened to them, and know how to fix this?