I had same issue for at least three months, feel like car stalling at ramps or at high speed, green key light flashing at same time. This green flashing is basically immobilizer anti theft protection, people will suggest to replace immobilizer coil, main relay, or ignition switch, after lots of research I only did two things, bought an injecter cleaner, mixed with gas while I filled tank, problem reduced, then changed all spark plugs, NO PROBLEM after that. spark plugs were really bad. never changed for 8 years.
Why this immobilizer key should flash for missfires I dont know, but bit weired for sure.