Originally Posted by upallnight

While testing the fuel pressure you can start the engine and stop it and observe how long it takes the pressure to drop. Try starting the engine and if it doesn't start note the pressure reading. Once the engine does starts note the pressure reading. With an assistant observing the pressure gauge snap open the throttle and observe the pressure gauge. If the pressure doesn't go up when you snap the throttle open you may have a bad fuel pump or a leak in the vacuum line to the pressure regulator. If the pressure reading goes up you have another issue that is causing a lean off idle condition like a vacuum leak.