I have a 87 montero and I been swapping a 3.0 6g72 sohc for the old 4g72 and have replaced distributor, rotor, cap, coil, plug wires, ecu, ignition module and still struggling with a no spark condition. I get a constant pulse when checking the ecu with my led test light, which is normal from what i gather. I have verified that i get a good cps signal at the distributor and I get a good signal from the ignition module. I use a spark tester at the distributor for testing. I'm stumped. I am wondering what the best grounding locations would be.