Reserve Fuel jerks!

Hey guys,
A zillion dollars for solving this mystery! I have an Escort 1998 Zetec 1.6 petrol. Last month, when it came on reserve, ie, when the fuel guage needle went into the red zone, the car started giving jerks. I showed it to an authorised dealer and got the following done:-
Cleaned the fuel tank.
Cleaned the fuel filters.
Ran an additive through the fuel pipes to get them cleaned.
This had no effect. As long as there is adequate fuel,ie, above the red mark on the guage, the car runs beautifully.
I was told to always keep the fuel above the red mark! But that is an ad hoc solution.
SO WHAT'S THE PROBLEM HERE? Can something be done about this?

Just a guess when the tank is that low on gas it could possible be that the fuel pump can't get to the fuel too little perhaps. However this is just a guess.

Just a guess when the tank is that low on gas it could possible be that the fuel pump can't get to the fuel too little perhaps. However this is just a guess.
Thanks Turtle. So that means I've gotta replace the fuel pump with a new one? Hell's Bells!! It's gonna cost a fortune! I'm dead!

It could be the tank design. The sending unit on the pump could also be off, ie, when you're reading the gauge to just hit the red zone, the reality could be that you're running on fumes. How far does the needle read when you top off the tank?

It could be the tank design. The sending unit on the pump could also be off, ie, when you're reading the gauge to just hit the red zone, the reality could be that you're running on fumes. How far does the needle read when you top off the tank?
UC, Thanx. I'll fill her up and check out. Crossing my fingers you're right!!