I have the old "Innovate Motorsports LM-1" (was super expensive back than) that comes with a wideband probe that you stick into the exhaust (so no bung welding).
On cylinder 1,2,3, I get around 14.7(ish) as it should be but on 4,5,6 it's through the roof.
Through the roof lean? Or through the roof rich?
