Here's my question: If there's an issue with exhaust flow through the precat, and you simply install a mil-eliminator, how is that a thorough solution? Seems to me it's the precat that should be getting the attention.
If there are no issues with performance, could there really be a problem with the precat itself? Changing out the downstream O2 sensors won't solve the problem, I take it?
have to remember that the original pcm programming had the limits set to tight ... you would get a pre-cat code (p0420 or p0430) when it wasn't real. I had them on my car but I really don't think that the pre-cats where shot nor plugged. Ford did reprogram a number of cars to correct the CEL from turning on when it shouldn't.
so the mil-eliminator is there to turn the cel off.