I have a 1996 F-150 ext cab 4x4 with a 5.0L. I am thinking that my cats are starting to plug. Is it possible to hollow them both out without screwing up the dual oxygen sensors. I have been told both ways with two O2 sensors. One sits before the first cat and the second is after the second cat. I am starting to have a sluggish feel on acceleration. Has anyone hollowed out the cats before with any problems? Just looking for some info and input.

 

You will throw codes if you hollow out the second cat. They're not that much to replace, and a good exhaust shop can diagnose whether the cats are causing the problem.

It could be MANY other things - have you pulled the codes? Checked the timing?