I had the same problem as the initial post. Cruising down the highway and the car would shut off for a second and then turn back on. Sometimes at light the speedometer would start bouncing, and I kept blowing the number #2 spark plug. Dealer kept replacing alternator. However, I discovered there was a recall on for the Taurus earlier model than mine, but same engine. The issue was the ignition coils were failing due to the fact that they were right next to the firewall and the temp was higher than the coil was rated. I changed my coil and all plugs and the problem was cured instantly. I do not know if my issues are the same as all the posting, but the sound very similar to some of the postings. | 
