Hi,
An easy check is to install a fuel pressure gauge on the fuel rail, pass side front at the schrader valve. With the key on, engine off it should be 39 lbs. with engine running at idle= 30 lbs, the vaccuum brings the pressure down.
Shut engine off, the fuel pressure should stay at 39lbs for at least 10 minutes, then slowly creep down. If the pressure falls right away you have a leak at the fuel regulator or a bad injector, either will cause a rich condition.
Good Luck,
Perry
