Has anyone had a #1 primary slip fit throw off o2 readings? I am wondering because it appears that I am getting low blm numbers on my drivers side and slightly lean blms on my passangers side. (approx 111/130). I am just curious if I should seal up this slip fit joint, the headers are used so it didnt really feel that tight but I dont see major leaks.

 

TTT

 

If there were an air leak somewhere before the O2 it would cause the O2 to appear lean, the only slip tubes I know of are on the drivers side header setups.