Q: Vehicle stalled at 75mph after 30 minutes of driving. Code for pump. Gauge said 1/8th but tank was dry.

No previous loss of power, missing, or other problems. I did reset the computer to no avail. Garage said it pulled code for fuel pump, but I won't have the code until Monday. I'm suspecting at least a fuel gauge relay, to address the inaccuracy. Once the car was filled up 1/2 it was running again. If the pump had failed I would expect some difficulties with starting that aren't present. I'm suspecting I have some residue or debris in the lines or the tank itself- causing the relay issue and potentially damaging/impacting the pump. I will replace the fuel filter for good measure. I don't trust the garage (who wanted to order a new dash unit because I have an LED range in the DIC)... I'm not sure if they can test the pressure (they may not be equipped)... I'm handy but I don't have a lift. Should I have the lines flushed? I'm concerned about doing damage to the engine if I drive it before this is resolved. What's the most cost effective way to approach this? Thank you!

My car has 72412 miles.
My car has an automatic transmission.