96 sable check engine light

Help!!!! I have a 96 Mercury Sable with about 45,000 miles, 6 cyl. overhead valve. My check engine light keeps coming on, sometimes solid and sometimes flashing. I have hooked up to the code checker and it always gives the code for misfire on 3. I have replaced the plugs, wires and coil and it's still continuing. I have also noticed that when the engine light flashes, the a/c compressor cuts off. Any help is appreciated.

This sounds like an electrical power issue that I have encountered. Does your engine surges intermittently when this light comes ON? When I experienced on my vehicle, I have my alternator and battery tested at autozone (they don't have to remove your alternator and battery).

Is the engine surging when you see the check engine ligh flash?

Thanks for the input. I have not had the engine surge, but it does idle roughly while the check engine light is flashing. I have learned to pull over and shut the car off completely and wait a minute. When I restart the car, the light is still on but not flashing and the a/c works properly again and the car runs smoothly. Later on it will start to flash again

Check for a vacuum leak and in my case the idle was bad and gradually became worse. Come to find out that the vacuum hose was rubbing on the egr pipe and slowly burning hole through it and the way it got burnt is that the egr pipe is somewhat blocking the hole it created on the vacuum hose. Replaced the hose and all is well.