Low Fuel Pressure - electric fuel pump

Basics,
What type of fuel pump?
Where is it mounted?
Have you checked voltage at the fuel pump?
Have you taken any readings right off the fuel pump, both pressure and flow?
Do you know for sure the gauge is accurate?

My .02 is that if you truly had 1.5 psi or 6 psi sitting at a light idling, either one wouldn't matter, you are using hardly any flow of gasoline and the bowl should be pretty much full not causing a idling issue. Especially if it runs down the road just fine when you are using a much greater volume/flow of gas.
It might be something other than fuel pump like the carb. is flooding out when idling.