1995 Buick LeSabre

Installed new fuel filter and fuel pump but only get 10-12 lbs of pressure on guage. What do I check next?

Do you think that gague is correct? I conclude car died and you decided to install new pump and now car still does not run?

Any idea how much voltage is getting to pump?

I believe the gauge is correct. I have been having trouble with the car not starting well and running roughly. i took it to the dealer and they said the fuel pump was only putting out 20psi and needed to be replaced. I put in a new pump and both filters and now it is only reading 10-12 pounds of pressure and drops off to zero over time. I could idle but when I step on the pedal it dies.

The fuel pressure regulator would be the next thing to check.

The car could not run on 10-12 psi.

The pressure should hold steady, if it drops off then there is a leak in the system. As mentioned the fuel pressure regulator might the the cause, remove the vacuum line from the regulator and check for fuel. If there is fuel present the diaphram in the regulator is ruptured and it will need to be replaced.

To check to see if the fuel pressure regulator is bleeding off too much fuel pressure, pinch the fuel return to tank hose from the fuel pressure regulator. If the fuel pressure goes up to specs, then, the regulator is faulty. http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?fromSearchPage=true&pageId=0900c152800b1e93&partName=Electric+Fuel+Pump&partId=0900c152800b1e93
Low voltage to the fuel pump can lower fuel pressure. You need to check that voltage at the fuel tank.
Kinks in fuel lines, and debris in fuel lines and fuel hoses can lower fuel pressure. You could check fuel pressure between the fuel filter and the fuel pump. If the fuel fuel pressure is higher, there is something in the lines or hoses which is causing it to drop. Examine hoses and lines.