Land Rover Repair: Running rich, labadie mo, discovery 3

Question
Have 1995 discovery 3.9 eng runs rich, black smoke, black plugs, diagnose display always reads 03 never changes, tried to read codes like you told me in the past but unable to read now like I said running rich can't seem to figure out need your help. Has new 02 sensors new plugs readjusted idle also srs like in middle of dash blinks sometimes just Last sr( s) sometimes all of it flashes. Hope you put some insite on this for me. Please and thank you very much my mane is Robert Otto bowers labadie mo.  

Answer
At this point I think you should get hold of the factory workshop manual and go through the step by step tests for the fuel injection.  They have a complete sequence in the manual, and all you need is a multimeter and hand tools.  That will be more likely to lead to a solution that parts changing