4A-GZE MK1 Engine Power loss / cutting out at 5500-ish RPM

4A-GZE MK1 Engine, fuel, coolant, ignition, plugs, system, switch, consistent, cooling, thing, cutout, cutting, sensors, swap, randomly, hopes, side, function, fuel-delivery, 5500-ish, made, failures, note, solved, decision, radiator, location, adding, reservoir, recovery, marty, wrong, filling, taking, bleed, setting, loss, realized, quart, bleeding, consistently, covers, replaced, valve, resealed, 5500, wires, discussions, needed, read

My son and I are slowly resurrecting a 1988 MK1 SC. I have read partial discussions about cutting out at 5500 RPM but no real solutions. It behaves as if it becomes starved for fuel or the ignition is acting up. We noticed that the plugs were literally soaking in oil, so we resealed the valve covers, replaced the plugs, the wires, the cap and the rotor (all of which needed replacing). We bled the cooling system. Now it pulls hard until the cutout. I am confident this is some sort of ECU thing