I am surprised there are no responses yet on this one. Has low pressure from the city water feed always been a problem or has it just started recently? The first guess would be a kinked water line inside the coach, especially if that water line runs through or near a slide which could cause a kink from moving in and out over time. Trace that city water line to wherever it connects into the main cold water line of the coach and see of you can find where it is kinked or crushed. The other issue may be if you have a manual selector valve that enables city water flow that is not in the correct position etc.
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