I have a 1987 mazda rx7 NA with emissions delete headers and exhaust. It runs on 1 rotor and I can't figure out why. What happens is if I have the upper intake manifold off and all the injectors removed and disconnected for about a day or 2 it'll run fine for like a half a mile. I've tested the ignition coils and the resistance was within spec. The injectors function and are not clogged and resistance is within spec. Replaced the spark plugs, plug wires, swapped a known good ecu still the same issue, replaced the fuel filter, noid light tested the injector wires and it lit up and still didn't work. Has excellent fuel pressure. Compression tested it and its was fine but even on all rotor faces and runs fine when the issue isn't there. But when everything is together and sits for a while it still runs on 1 rotor. I'm thinking it might have corrosion in the engine harness. Any help would be appreciated