Upon start up and for the first ten minutes of driving, fuel pressure is normal. After the car warms up it begins to drop off in a linear fashion until it's down to 25 psi at idle. The fuel pressure regulator and damper have been swapped out to no effect. The fuel pump ohms fine. Nothing appears to be burnt or blown inside the fuel pump controller case.
The car had been sitting for about 6 months. I drained the tank but some of the old gas was circulating through the system when I was switching on the ignition to check some wiring. A new fuel filter is on the way so that might be it (but why would it run fine for ten minutes if it was clogged?)
