I've got a 1954 Chevy pickup that I put a 5.3 from a 2012 Tahoe with a 76mm turbo. I've got my wastegate plumbed in directly before the turbo, dumping about 8" after the turbo. My wideband O2 is mounted approx 8-10" after the wastegate 6ish ft before the exhaust tip.

While driving and stopped in gear, the WB O2 reads as expected, but in park, it is reading around 11:1. I did a free air calibration on the wideband O2 and it didn't change anything.

I have been going back and forth with a tuner doing an email tune and he says something is wrong with my setup, but I am not so sure. Does anyone on here have any ideas on why the O2 is reading like this? I have attached a quick log from today along with my tune.

Any help is greatly appreciated.

Thank you,
Austin