Ford Repair: running rich, fuel pressure regulator, k n air filter

Question
I have a 1990 ford mustang 2.3L efi . It idles smooth and runs great but the fuel consumption is horrible about 4.5G/60  miles( 16.2L/100km).  There is also black smoke in the morning when I start it for about 5 secs. Is the engine running rich and if so is there a fuel mixture adjustment or anything that I can try to fix this? I have already replaced the K&N air filter ( saved it )with a new paper filter and had no luck. Any help would be appreciated, Thanks for your time.

Answer
first have it scanned for codes that might help decide which direction to go-then clean mass airflow-clean throttle bore and idle air control motor-pull hose off of fuel pressure regulator and make sure no fuel is in it if it is replace it-have ect sensor checked also could be sticking or dirty injector/s-also thermostat