2003 Ford Taurus

I have a 2003 ford taurus, that has been in the ford dealership for the last 2 months. As you are driving down the freeway, highway, etc. The fuel light comes on, then the theft light, usually when the gas guage hits 3/4 of a tank full, and it will start to stall. If you can press on the the throttle peddle, than it will not die. When the gas guage needle is on the 1/2 a tank line, all the lights go out, I loose the RPM guage as well as the speedometer. I have had 3 new fuel pumps, EGR valve replace, and numerous other relays, to have the dealership basically tell me they do not know what to do with it. The car only has 55 000 miles on it or should I say 56,000 now they have done all of their test driving. Please tell me if other people are complaining, about this situation, and if there is actually something that can be done to repair this car. Thank you