I'd go back to stock and clear the code, just to see if it comes back. If it doesn't, you'll know what the problem was. If the code comes back, the problem is elsewhere, but at least you'll know it wasn't the k&n setup.
i had a coolant leak problem which had to get fixed first... i took it to the dealership and they fixed it... it wasn't cheap... but whatever they did... also cleared the cel... i figured they would just clear it for me... but it would come back anyway since all they were doing was replacing the water pump and thermostat...
but ever since then... no cel... nothing... car runs great... and i've made no additional changes to the intake
