I recently did a lt1 swap of my v6. The lt1 is in, but it will nnot idle and runs very rich. The rich condition is in the left bank(1,3,5,7) And the o2 readings are around 8 on that side, the right side is ok at aound 400 on the o2 readings. The scan tools is reading open loop while the car runs. I got a new o2 sensor and still the same issues. When i unplug the MAF and air temp sensor the car seems to run alright, but still a little off on timing. Also, the low coolant light is staying on although it is full. When driving the car it feels like a carburated engine that misses and has a few plugs off! !HELP!

 

Crossed wires or other reason it's not firing probably 3 or 4 cylinders on that side.

Check your oil for fuel contamination.