Harvey,
Yes for a stock efi the fuel pressure should be 39 lbs without the vacuum line on and 30 lbs with the line on running at idle,you need to do this 1st. Too much fuel will wreck the oxygen sensors and the cats. If the oxygen sensors are black they are NOT working and should be replaced as the computer will go into rich warm up [choke] mode if it doesn't get the signal from the oxygen sensors. The only time they are not used is under full throttle so all other times you will be too rich.
Perry.
ps- a mass air system will do nothing for a stock engine,you only need it if you run a performance cam.