Some assistance please :) ?

Hey everyone, so I own a rx8 because they are the best cars ever ! And this winter I was repairing my 8 and I put in a new engine, new battery, new spark plugs..and I drove it for a bit but I needed new 02 sensors (back and front) so I did that and when I went to pick my car up it would not stay idle or neutral ..it would just die but it's driving and it felt better than driving it last year... But the only problem is that it isn't staying idle ... Does anyone know what this is and care to explain it please ? It would be highly appreciated



Thanks .



Alvin.