2004 Tahoe 5.3Z Flex 235K miles
Overall vehicle runs good but does have a few misfires at idle in bank 2. The only issue is at idle the LTFT bank 2 is around 11.7. Bank 1 is 4.8.
When going 65 @ 2000 RPM both banks are often exactly the same around 11. STFT works perfect around 0, jumping ± 4. In addition the O2 sensor voltages seem normal jumping around from .2 to .8 volts on both banks…
I have heard that older engines may have a higher LTFT but I am curious is there is anything else I can try to get LTFT down closer to 0?
From my understanding O2 sensors are detecting a slightly lean condition causing the fuel trims to be a little high. My intake gaskets are new and I have performed a smoke test and it shows no leaks. I have a new MAP, CPS, Injectors, Fuel Pump, FPR, Plugs, Cables. All relearns performed, fuel pressure dead on spec.
Ideas I have to optimize my fuel trims are:
Clean or Replace MAF
Replace O2 Sensors (235K miles)
Determine if I have a small exhaust leak on bank 2.
Does anyone have any feedback or input?