A gasoline engine will misfire at 22:1 a/f ratio. I think your readings aren't accurate. You may be getting reversion and the sensor is reading air being drawn back into the exhaust. Where did you install it?

Last edited by Blusmbl; 01/22/14 09:32 PM.
'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118