87 Honda Accord DX: Loses acceleration after reaching 50 mph

87 Honda Accord DX, Carburetor. 197K mileage

Problem:

The car starts normally and runs fine; however, on the freeway after reaching 50 mph, the car suddenly loses acceleration, I'm unable to accelerate pass 50

mph, stepping on the gas to the floor gives no response.

During the loss of acceleration, the engine does not die, it keeps running. Once the car is slowed down to below 50 mph, for example, back to 20, 30, or 40

mph, I'm able to accelerate again to 50 mph.

Diagnosis from Shop: Diagnosis fee = $50

I took the car to a shop for a diagnosis; they checked to see if catalytic converter was the problem, they tested this by taking off the catalytic converter

and driving the car without it. They said it wasn't the catalytic converter. They said it's either the Electric Fuel Pump inside the gas tank or the

carburetor or both, but need to start with Electric Fuel pump first.

Estimate given by the shop: Electric Fuel pump and labor = $600


Question:

I don't know too much about fuel systems; however, does the diganosis seem right? If anybody has any suggestions I'd appreciate it.

Thanks.