Is the single overhead cam 3.0 liter engine the same as the one used in the pickup and pathfinder? If not What is the difference between them.

 

The long block is the same. The stuff that attaches to it, however, is different. Early pickups and Pathfinders had throttle-body fuel injection and only made about 145 HP. Later models had multi-port injection and made 155 HP, I believe.