I've seen my gauge mounted on my 2-port reg. go pretty low like that at idle as well with a mech. pump. How long is the line to your gauge? Maybe when the bowls are filling the fuel could back down the gauge line? Maybe try taking the line from the hood and watch a gauge sitting on the floor? If the car isn't running out of fuel I have to believe that the pump is fine. They are a pretty much work or don't work kind of thing. My .02...
Yea I dont know if maybe the gauge is sticking high on pressure?
I have maybe 3 feet of line. It holds pressure for several hours.
I guess if the float bowls lost pressure back into the lines and the gauge stuck it would show like this.
Sure seems like the gauge responds quickly to changes though while it's being driven.
When the throttle opens quickly, the gauge drops right away.
