problem not resolved yet. I replaced the fuel pump relay with a new one, but the still the same problem.
*with the relay installed, it would idle fine (voltage at fuel pump=13.3V) for a while then goes to rough idle (voltage at fuel pump=12.5V) and finally dies. Both fuel pumps also continues to run while idle is rough
*Without relay installed and with pins 7 and 8 shorted, the car idles smoothly. I had the car idle for an hour and with no problems.

I appears that some other part upstream supplying the fuel relay maybe causing the problem. Any ideas?