[RikNMort23]

Hi All,

I've got a 2016 1SS. In August of 2022 I had a Cam/headers installed at a shop that also did the tune. Everything has been fine with the car except I've had this CEL come on intermittently that started during the summer of 2023. First time it came on it was a P0171 and P0174. Lean condition bank 1 and 2. I would find that my intake duct(RotoFab) had some play in it, so I would tighten the clasps and the CEL would disappear for a month or so. CEL came back on and same thing. Tighten, then CEL went off for a few months.

Well now I'm having trouble passing emissions, CEL has come on, same P0171, P0174 codes. I have Fuel system, O2 Sensor and I believe EGR systems "not complete". So I'm trying to resolve the core issue.

Reading live data, I would find that LTFT start fine on cold start up(3-6%) but then tend to get worse as the car heats up (7-10%) at idle. Things only get worse as I start to drive. On light acceleration LTFT hang around (7-10%) when I let go of the accelerator LTFT will jump up to (16-19%) but then come back down to (5-9%) but once I come to a full stop it quickly climbs (16-25%). STFT always seem to be anywhere from (-5 to 5%).
Bank 1 LTFT is always worse than Bank 2. Bank 2 is usually like 4-5% less than Bank 1.

Ive done a smoke test from the intake and found the boot right after the MAF was still leaking a bit. Ive changed the clasps and seems to have fixed the leak at the boot but Fuel Trim numbers seem to still act the same. Oxygen sensors seem to be switching like they should but I'm not sure if they're switching late or not.

Ive tried cleaning the MAF since I have the oiled filter. MAF readings seem to be normal. About 6 g/s at idle. I did notice that the MAF will hang around 9 g/s immediately after coming to a stop. But after idling for a bit will drop back to 6 g/s.

Ive done a smoke test from one of the evap tubes from my oil catch can and didnt see any other leaks.

Any input on what else I should be checking or maybe I'm missing something obvious?

Appreciate any help. FYI CEL is not currently on, but those fuel trims don't seem fine to me

[easttxss]

Check all your header bolts at the heads and look for the black, sooty, signs of an exhaust leak between the head and the header flange. The O2 sensors are very sensitive to exhaust leaks. You may also have to replace the header gaskets if you can't get them to seal again. Only go with the GM/Mahle gaskets. I also turned off LTFT as it would keep creeping up like yours.