2006 sienna
if the air filter housing doesn't close properly ,can that cause a lean problem.
I just replaced all o2 sensors, maf sensor,spark plugs, all coils,platium intake gasket and im still getting the lean codes po171 & po174. the van runs good.
I erase the codes and they dont come back right away, I can drive it for a week and then it comes back after i drive it for more than 200 miles..