problem w spitting and sputteribg lack of compression

When the car is cold it seems to run fine but as soon as it gets to reg temp it starts to spit and sputter and appears to loose compression. and the cel starts to blink fast. the obd said it was a misfire in cylinder #4 so i replaced all 4 plugs the wires seemed fine .however it didn't change anything. now i was told that it could be the ignition module. because it was V E R Y H O T AND WAS MELTING THE BOTTOM PART OF IT. I ONLY DROVE THE CAR APPROX 10 MIL AFTER REPLACING THE PLUGS WHEN THAT PROB ACCURED AND THE LACK OF COMPRESSION AND THE SPITEN AND SPUTTERING JUST AS IT DID B-4 I REPLACED THE PLUGS. SO WHAT DO U THINK IS THE PROB ? R U FAMILIAR W/ THIS IGNITION MODULE