3.0i headers

[dabenthusiast]

Originally Posted by Ricky Bobby

Run the 90 degree spacer on the post o2 sensor only - the pre-cat o2 sensor should be installed right into the bung on the header.

This way the ECU sees the "difference" between the o2 sensors, there is a cleaner reading at the rear, the CEL should go away after a few drive cycles once you do that.

sorry i was little unclear, i only have 90 degree on post. and the pre cat is straight in the header.
p0420 code.
i cleaned mass air flow sensor and o2 sensors are fairly new. maybe they are the bosch ones.
iv heard that bosch might not work with the spacers..