[kdizzle781]

I've been doing quite a bit of reading about the pre-cat failure and all and i am very interested in replacing the exhaust manifold with new headers. Im looking to support MarkSpecV. Any1 recommend MarkSpecV's headers? Easy installs? still works? build quality?

Anyway here is the real question i had about replacing the headers...

I understand the point of the spacer on the 2nd o2 bung. It causes the o2 sensor to get less of a reading by recessing the second O2 sensor away from the exhaust stream. Which equals no light.

I guess my only question is wouldn't this mess with the air/fuel ratio because the ecm is no longer getting accurate readings? Decreased gas mileage? too rich? too lean?