Backfiring, Lean conditon on th3 4.0? Sept 30, 2008 22:50:00 GMT -5 Select PostDeselect PostLink to PostMemberGive GiftBack to Top Post by XJLI on Sept 30, 2008 22:50:00 GMT -5 just wanted to say i was losing power and my jeep felt reallly lean then i put in a new MAP and all was well.