During highway driving last night I lost power momentary causing a slight loss of power. The RED Theft light came on solid for a few seconds indicating the ignition power was restored. Power returned quickly. Happened 3 times.

Where do I start to fix?

THANKS

1999 GREEN Contour SE SPORT Duratec V6, ATX, SUNROOF, 93,000 Miles, P0420 ON&OFF -replaced DS O2 --did not FIX *New TORQUE CONVERTER @ 53,000-Intermittent P1744 *New DASH at 53,000 and New DASH lifted-now using MOLLEY bolts to pull down