So yes all I have is a narrow band autometer A/F. Its always done full sweeps lean to rich up till about a month ago. Now with my car having 112k on it I was thinking the fuel pump was starting to get weak ,car also randonly was dieing during idling or sometimes even switching from drive to reverse. I've done quite a few fuel pumps at work(nissan) for dieing problems. So I got a new pump and installed it today along with a new fuel filter.

First start up the gauge was going into the green again no issues, so i was obviously pleased. The car sat for a little while, while I tinkered with some other stuff. Started it again and all the gauge was doing was going red and yellow, maybe 1 green light. Anyone have any ideas of what else could be hindering my fuel ratio's? For reference I'm running the GM tune with 3.0 pulley and stock SS injectors. Yes I know people have had lean issues with this set up but thats at high rpm not idle and just cruising.

Going by a narrowband for fueling is just non sense. Could be your O2 sensor going out. Need to get a reading with a datalogger and see what the O2 sensor is doing. My bet is the sensor.



FU Tuning

I COMPLETELY agree. I've just had the gauge in the car for a LONG time and its starting to act up now. Just looking for ideas on things to check