my 91' 740 is experiencing the first cold winter in Wisconsin after 11 years in the southern states. last week the car suddenly won't start, I towed it to a garage, and they said that the fuel pump(regina FI system) is broken they changed a new main pump and a new pump relay. However the fourth day I got it back from the garage, the car died on the high way. it looks like there is no gas inside the tank while the gauge reads 1/4, I add in exactly one gallon in, and it started and run perfectly, I drove it to the nearest gas station and fill it up with another 8 gallon gas, so far you can see that there should be another 5 or 4 gallon left inside the tank befor it died on the road.
I am pretty sure that the gauge is correct, cause when it reads 1/2, if I add another 7 gallon, it will read full. but the garage people told me that my fuel sending unit is in faulty. they said that may be cause by the faulty fuel gauge.

What is your diagnose?

I can't believe what he told me!

Please help me.

Thanks

Lux