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Help: Idle / Cruise Lean Issue
Hello! First time poster, long time lurker. I have been having pretty decent success with tuning my first Gen 5 car. I have previous experience using Megasquirt on my Turbo Buick. I have a 2016 Camaro SS with LT Headers, no cats, Ported IM/TB, and a Rotofab CAI. I had a track rental in April where I ran 11.66 at 120mph. After the rental, however, I have been having this odd issue. At first I thought it was maybe bad gas, but after three full tanks, I decided that couldn't be it. The car will warm up normal with lambda climbing from 0.85x to 1.0 as idle rpm lowers. After a few minutes, it starts to go lean, sometimes climbing up to 1.15 lambda. Trims are all over the place with Bank 2 typically being much higher than Bank 1. Bank 2 seems to be pegged rich. I have replaced this sensor with a brand new AC Delco unit and the car has brand new plugs and wires. I thought it may be a misfire issue, hence the plugs and wires. It still COULD be I suppose.
All plugs and wires seemed in good shape when they were pulled. I didn't notice anything abnormal.
Before this issue, I had trims pretty close, being within 2% on either side. Fueling seems to be okay under throttle, but I have not been stepping on it much since I noticed this issue. Trims do not seem to change with VVE. Putting the car in open loop at idle, it goes even more lean. My WB was seeing 1.20 lambda. I shut it down quickly. I tried MAF only and Speed Density closed loop and nothing seemed to change.
I am posting a tune and a log. If you have any thoughts, I would really appreciate any and all input. I am lost on what to do next.
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