2000 Montero sport was running great then one day started to get sluggish and idle bad. then throughout the day just got worse to where it'll barely run and no power at all. Checked plugs and they were full of oil. I replaced plugs, wires, and valve cover gaskets. Zero change. Tested continuity on power transistor 2 prongs did not have continuity. replaced with one from salvage yard that has continuity. Zero change. Pulled the covers off and timing is on the nose. Replaced cam position sensor with zero change. When I pull plug wires off of coil packs there is no change until I get to the first coil 3/5 the vehicle dies. There is spark coming out of the other 2 coils but it is weak. Tested all coils with multi meter the resistance tests fine. Went thru diagnostics tree lead me to believe it's a bad ecm so I replaced that with zero change. I really am lost at this point. I'm suspecting the power transistor unit but don't want to replace any more parts just to be left with zero change. If anyone could point me in the right direction of what I may be overlooking I would really appreciate any and all input.
Forgot to mention I also replaced the fuel pump and fuel filter
Thanks in advance for your time