Ok guys, I have an 02 montero sport that started missing about a month ago very noticeable going up hill or with a load on the engine I replace the plugs and wires and no luck any suggestions? Thanks in advance

 

This may sound crazy but It may be torque converter shutter. I've seen it many times. If you can afford it, you should flush the transmission and use Mitsubishi fluid. Very old fluid or the wrong fluid can cause this condition. Let me know how it comes out.