Air Fuel Ratio Gauge problems

[88fivepointoh]

I installed a phanton face air fuel ration gaige this weekend and it doesn't seem to be working correctly. when i first start the car cold, the gauges slowly lights up to the near rich point. after it warms up the gauges doesn't show any lights at all. when I rev it it goes to almost rich but fluctuates from no light to rich. when I am driving the gauge does the same thing and never stays steady even when I am on the throttle. could I have bad 02 sensors? I do get a code for always lean condition with no change. but when I get on it, it does go in the rich area? Fuel pressure it set to 38lbs with vac. ON. any ideas?