1999 Mercury Sable ENGINE LOOSES SPARK WHILE DRIVING

I drive this car 150 miles each day. It runs fine except for this new problem that has started. The motor seems to loose spark for 1 or 2 seconds. Then will perk right back up as if nothing is wrong. I still have electrical everywhere else such as dash lights, radio and headlights during the engine power failure. The service engine light never comes on during or after the lose of power. I do get some dash lights that come on while I have the power lose. The fuel light being one of them. There are others that come on, I see a glow from the other side of the gauge cluster if it happen when the sun is down, but I never catch which ones came on. It happens randomly and is over very quickly. I always have gas in the tank. I have had checked the fuel pressure and flow and it was good. It can happen during acceleration or while my foot is on the brake at a light. Last summer it seemed to be happening every week at least once or twice. I changed the spark plugs for the first time in the life of the car. The problem went away for about 3 months, then happened one time. I am now waiting for the big one to strike. I don't see a ignition module like the older cars. What do I check or replace now? The computer?